Five checks before a final notice#
A final notice to a client who never received a correct invoice is an embarrassment you cannot take back. Check your own side first.
- The invoice is right. The legal entity, the PO number, the amounts in the SOW. If anything was wrong, fix that first; the overdue invoice email has the letters for it.
- There is no open dispute. If they questioned a line and you never answered, answer it. A final notice over a live dispute escalates the dispute, not the payment.
- The earlier letters went out. You can name the dates of at least two reminders and the person each went to.
- The MSA says what you may do. Find four sections: payment and interest, suspension of services, disputes, and notices. The notices clause often says a formal notice counts only if it goes to a named address, sometimes by courier, with a copy to their legal department. An email to your contact may not count.
- You have called. The person who signed the SOW, not AP.
The call before the letter#
The call is five minutes and one question. You are not reading the notice aloud; you are giving them a last chance to solve it without one.
[Name], I am calling about invoice [C-1093], [$36,000], which is now [39] days past due. We have written to your AP team three times without a payment date. I do not want to put this in a formal letter, so I wanted to ask you directly: what is holding it, and what date can you commit to? [Listen.] Thank you. I will confirm that date by email today.
If they give a date, confirm it in writing within the hour, and hold the final notice until the day after. If they offer instalments, see the payment plan below. If they do not pick up or will not give a date, send the notice.
What a final notice may say, and when#
| What | Only if |
|---|---|
| The invoice, the amount, the days past due, the dates of your reminders | Always. These are facts. |
| A date to pay by, usually 7 to 14 days out | Always. One date. |
| We will pause the work on [date] | The MSA gives a suspension right, and you give the notice it requires |
| No new SOW or change order will start until it is paid | Always your choice; you are not obliged to start new work |
| Interest at [rate] from [due date] | The contract provides it, or UK law does for a business debt |
| We will refer the debt to a collection agency | You have chosen one and will do it on that date |
| We will start a claim in [small claims court / the courts] | You will, and you know the court's limit and fee |
| Our lawyer will write to you | You have a lawyer ready to do it |
What a final notice must not say: anything untrue, any step you have not decided to take, and anything about the client to anyone else. In the U.S., the federal Fair Debt Collection Practices Act covers debts of a natural person for personal, family or household purposes,1 so a services invoice to a company falls outside it. State laws and the law of defamation do not stop applying. Keep the letter to facts and dates.
The final notice template#
Final notice for an unpaid invoice
From the founder, to the person who signed the SOW, with AP and their legal contact in Cc. Also send it to the notices address in the MSA, the way the MSA requires. Attach the invoice and the reminders.
Dear [Name],
Invoice [C-1093] for [$36,000], for [phase 2 of SOW 4] under our Master Services Agreement of [date], was due on [October 1, 2026]. It is now [46] days past due.
We wrote to your accounts payable team on [October 6], [October 13] and [November 2], and I called you on [November 9]. We have not received a payment or a payment date.
Please pay the full amount by [Monday, November 30, 2026], by bank transfer to the account on file or here: [payment link].
If payment has not reached us by that date, we will pause all work under SOW [4] from [Wednesday, December 2], as section [9.2] of the MSA allows, and resume it within [two] business days of payment. Under section [7.3], interest at [1% per month] accrues on the overdue amount from [October 1].
If any part of the invoice is in question, tell me by [November 23], and pay the rest by the date above.
Sincerely,
[Your name], [title], [Your firm], [address]
Re-send the invoice too. Attach a fresh PDF of the same invoice, same number, with “FINAL NOTICE” and the pay-by date at the top, and the days past due and any interest the contract allows as separate lines. Do not issue a new invoice number for the same work: their AP matches the number they already hold.
The notice that pauses the work#
If the date passes, the pause often brings the payment, because it touches the project their team is waiting on. Send it on the day you said, in the form the notices clause requires.
Notice of suspension of Services. Reference: Master Services Agreement dated [date] ("MSA"), Statement of Work [4]. Invoice [C-1093] for [$36,000], due [October 1, 2026], remains unpaid after our final notice of [November 16, 2026]. Under section [9.2] of the MSA, Provider suspends performance of the Services under SOW [4] effective [December 2, 2026]. Provider will resume the Services within [two (2)] business days after receipt of payment in full. Deadlines in SOW [4] that fall during the suspension are extended by the length of the suspension. This notice does not waive any other right of Provider under the MSA.
The sentence about deadlines matters: without it, the client can say you missed a milestone while you were paused.
If the MSA has no suspension right, you cannot pause the current SOW without risking breach. You can still decline to start a new SOW or change order until the invoice is paid, and you can ask for a suspension right in the next MSA. The late payment fee clause and How to review a client’s MSA have the wording.
In the UK: the letter before claim#
Before a court claim in England and Wales, the courts expect a letter that sets out the claim and gives the other side time to answer: the Practice Direction on Pre-Action Conduct says 14 days in a straightforward case.2 When the client is an individual or a sole trader, the stricter Pre-Action Protocol for Debt Claims applies instead, with 30 days to reply;3 between two companies, it does not.
A UK final notice can be written as that letter:
Letter before claim. We write about invoice [C-1093] for [£28,000], dated [date], for services under our agreement of [date]. It was due on [date] and remains unpaid. We claim the invoice amount, statutory interest under the Late Payment of Commercial Debts (Interest) Act 1998 at [8% above the Bank of England base rate] from [the due date], and fixed compensation of [£100]. Copies of the invoice and our reminders are enclosed. Please pay in full, or tell us in writing why you dispute the debt, within 14 days of the date of this letter. If we receive neither, we intend to issue a claim without further notice.
The interest and the fixed sums are explained in the overdue invoice email.
When they offer to pay in parts#
A client who cannot pay all of it now and says so is better than one who goes silent. Accept a plan when the dates are short and in writing, and make the first payment the test.
Thank you for the call today. As agreed, [Client] will pay invoice [C-1093], [$36,000], in [three] parts: [$12,000] by [date], [$12,000] by [date] and [$12,000] by [date]. Work under SOW [4] continues while each payment arrives on its date. If a payment is missed, the remaining balance falls due at once, and the final notice of [date] applies from that day.
If the date passes: what comes after a final notice#
Pick one, and do it on the day you named.
- Pause the work, if the MSA lets you, with the notice above.
- A demand letter from a lawyer. It costs a few hours of their time and often gets an answer the founder’s letter did not.
- Small claims court, for an amount under your state’s limit. The limit, and whether a business may file, vary by state; check the court’s own site before you name it in a letter.
- A collection agency, usually paid as a share of what it recovers. Read its contract for what it may do in your name.
- Write it off, when the amount is small and the cost of chasing it is larger. Then decide whether you work with that client again, and on what terms: payment on signature, a deposit, shorter terms.
Whatever you choose, keep the record: the invoice, every reminder, the call notes, the notice. Any of the steps above starts by asking for it.
Final notice subject lines#
Final notice: invoice [number], [amount], [days] days past due
Final notice before suspension of services: invoice [number]
[Project]: payment of invoice [number] by [date]
Letter before claim: invoice [number] (UK)
Put “Final notice” in the subject only once, in this letter. Used earlier, it means nothing when it is true.
Set up the reminders before a final notice in Tommos#
Tommos (tommos.ai) is a CRM whose AI agents, the tommos, take a B2B inquiry to a signed contract. On the Sign plan, Tommo Closer writes each overdue reminder on its day, from the deal’s record: the invoice number, the PO, the amount and the payment link. It puts the reminder on a card on your phone, and one press sends it. By the time a final notice is due, the polite letters have gone and the deal shows each one. The final notice itself stays yours: a pause of work, a claim or a payment plan is a decision about a client, and the founder makes it. Tommos charges no late fees and does no collections. The setup:
- 1
Connect Mercury
In Settings, Invoices, copy the address under “First, in Mercury, allow this address on the token”, allow it on your Mercury API token, then paste the token and press “Connect Mercury”. Tommos then reads each invoice’s status, so the reminders stop the day it is paid.
- 2
Decide when the reminders end
Open Tommo Closer, the job “Get the deal paid”, its Letter. Under “When it reminds of an unpaid invoice”, “At most” sets how many go before the invoice comes to you. With the defaults, 3 days late, then every 7 days, 3 in all, it comes to you about 17 days past due, well before the 30-day final notice.
- 3
Get the task, with the record
After the last reminder, a person gets a task for the invoice. The deal holds what the final notice needs: the invoice and its number, the count of reminders on the invoice’s line, and each reminder on the deal’s timeline with its date. The signed paper Tommo Closer read the payment schedule from is in the client’s folder in Drive, so you can check the notices clause before you write.
- 4
Call, then send the notice
Call the person who signed, as above. If the call brings no date, write the final notice from the template on this page, with the date to pay by and the one step your contract allows.
- 5
Let Tommo answer an objection
If the client replies that a line is wrong, Tommo writes the answer from the record of the deal and puts it on a card; you press Send. If the invoice must change, one card cancels it and makes the correct one.
Questions about final notices for unpaid invoices#
- What is a final notice for an unpaid invoice?
- The last letter before you act on an unpaid invoice. It states the invoice, the amount, the days past due and the reminders already sent, gives one date to pay by, and names the step you will take if payment does not arrive.
- When should I send a final notice?
- After two or three reminders and a call have not brought a payment date, usually 30 to 60 days after the due date. Check the invoice is correct and no dispute is open first.
- What should a final notice say?
- The invoice number, the amount, the due date, the dates of your earlier reminders, a date to pay by, and one consequence the contract allows, such as a pause of work under the MSA or the contract's interest rate.
- Can I stop work if a client does not pay?
- If the MSA gives you a right to suspend services for non-payment, yes, after the notice it requires. Without that right, pausing current work can put you in breach; you can still decline to start new work.
- How many days should a final notice give?
- Seven to fourteen days is usual. In England and Wales, a letter before claim to a company should give 14 days in a straightforward case; to an individual or a sole trader, 30 days under the debt claims protocol.
- Does the Fair Debt Collection Practices Act apply to unpaid business invoices?
- The federal act covers debts of a natural person for personal, family or household purposes, so a services invoice to a company is outside it. State laws can still apply, and nothing allows a false statement in a demand.
- Should a final notice come from the founder?
- Yes, at a small firm. It is a decision about the client relationship, and it carries weight when it comes from the person who signed the deal.
Key takeaways#
- Call the person who signed before you send a final notice.
- Check the invoice, open disputes and the MSA’s notices clause first.
- One date to pay by, and one consequence the contract allows.
- If the date passes, do exactly what you said, on the day you said it.
- In the UK, write it as a letter before claim: 14 days for a company, 30 for an individual or sole trader.
- Never threaten a step you will not take.
This is not legal advice. Before a pause of work or a claim over a large amount, an hour of a lawyer’s time is worth it.
Sources#
- 15 U.S. Code § 1692a, Definitions (paragraphs 3 and 5), Cornell Law School LII, read Oct 15, 2026
- Civil Procedure Rules, Practice Direction: Pre-Action Conduct and Protocols, paragraph 6(b), Ministry of Justice, read Oct 15, 2026
- Pre-Action Protocol for Debt Claims, paragraph 1.1 and the 30-day reply period, Ministry of Justice, read Oct 15, 2026
Read next
- Overdue invoice email: what to send 3, 10 and 30 days lateWhy invoices go overdue, the letter for each week, and the fixes for a missing PO, a wrong entity or a disputed line.
- How to get clients to pay on timeThe eight steps from the signed SOW to the money, the vendor setup email and the invoice checklist.
- How to review a client's MSA before you signTen clauses, the wording to send back, and the email that sends it.