Collection Letter

Updated October 30, 2026. Written by Salman Shawaf, Co-founder, Yonovo.

A collection letter is a written demand for a specific past due invoice, sent by the company that is owed the money. It names the invoice, the open amount, the due date, how to pay, and where to raise a dispute.

What a collection letter is

In B2B, the letter comes from you, under your name, to your customer. It is not a letter from a third party agency, and it is not a letter a consumer writes to dispute a debt. If you received an agency letter about a personal debt, use the Federal Trade Commission's debt collection guidance. Do not adapt the samples below for that.

A collection letter is one document. The series of notices that gets firmer as an invoice ages is covered in the dunning letter guide. Email versions are in the past due invoice email templates. These samples are examples, not legal advice.

What to include

Invoice number, original amount, amount still open, and due date.
How many days past due it is, so the reader does not have to calculate it.
A way to pay, and a reply path if the invoice is wrong.
On a later letter only: the next step and the date you will take it. Omit any step you will not actually take.

Send it from a person the customer knows. Yonovo sends follow up from the client's own domain, across email, SMS, phone, and WhatsApp, and pulls the invoice out of the sequence when the ledger shows it paid. That workflow is accounts receivable collections software. Seriously overdue accounts, still under your brand, are covered on debt collection software.

Collection letter samples

Standard collection letter

Subject: Payment requested: Invoice [number] for $[amount]

[date]

[customer name]
[customer company]

Please pay invoice [number] for $[open amount], due on [due date] and now [X] days past due.

Pay here: [payment link]. The invoice is attached.

If you have a dispute or you need a document before you can pay, reply by [date] and we will pause reminders on this invoice. If payment is already sent, reply with the reference.

[your name]
[title]
[company]
[phone]

Final collection letter

Subject: Final notice on invoice [number]

[date]

[customer name]
[customer company]

We have written about invoice [number] for $[open amount], due [due date]. It remains unpaid.

This is the last request we will send. Pay by [date] at [payment link], or send a written payment date we can accept.

If we do not have payment or that date by [date], we will [credit hold / the next step you have approved]. We would rather close this on good terms.

[your name]
[title]
[company]
[phone]

Pair the letter with the bucket on the aging report. A first letter belongs in 1 to 30. A final letter belongs once the invoice is well into 60 or 90 days and earlier notes had no reply.

Frequently asked questions

A collection letter is a written request for payment of a specific past due invoice. On this page it means a letter from the company that issued the invoice, sent to its own customer. It is not a letter from a third party collection agency, and it is not a letter a consumer sends to dispute a debt.

The invoice number, the amount still open, the original due date, how many days late it is, how to pay, and where to send a dispute. A later letter should also say what you will do next, and by when. Leave out threats you do not intend to carry out.

No. These samples are for a business collecting its own commercial invoices. If you are a person who received a letter from a collection agency, use the Federal Trade Commission's debt collection guidance. Do not adapt these templates for that situation.

Most B2B teams send a short sequence over the first 90 days, then decide: payment plan, credit hold, or a referral you have already described in the final letter. The number matters less than sending them on a schedule and stopping when the invoice is paid or disputed.