A three-step overdue-invoice sequence drafted with AI, with placeholders and real policy only

The prompt

Paste this into ChatGPT, Claude, or whichever chat tool you use:

Write three short reminder emails for an unpaid invoice.
1) Friendly: a few days past due. Assume they forgot.
2) Clear: about 10 days past due. State the amount and
   date plainly and ask when they will pay.
3) Firm: about 3 weeks past due. Polite but direct. Ask for
   payment by a specific date and offer a quick call.
Rules: no threats, no guilt, no legal language. Keep each
under 120 words. Use these blanks exactly: [CLIENT NAME],
[INVOICE NUMBER], [AMOUNT], [DUE DATE], [PAYMENT LINK],
[MY NAME]. Don't invent fees or policies.

The blanks matter. You don't need to give an AI your client's name or the amount to get a good email.

What the three can sound like

These are illustrative, not a script you must use:

• Friendly: "Hi [CLIENT NAME], a quick reminder that invoice [INVOICE NUMBER] for [AMOUNT] was due on [DUE DATE]. Here's the link in case it slipped through: [PAYMENT LINK]. Thanks!"
• Clear: "Invoice [INVOICE NUMBER] for [AMOUNT] is now ten days past due. Could you let me know when it will be paid?"
• Firm: "Invoice [INVOICE NUMBER] for [AMOUNT] is three weeks overdue. Please arrange payment by [DATE]. If something is holding it up, reply and we can sort it out on a quick call."

Add only your real terms

If your contract or invoice says there's a late fee, you can mention it in the third email, using your exact wording. If it doesn't, leave fees out. The same goes for pausing work or sending the debt to collections: only say it if it's true and you'd actually do it. AI will happily add a fee you never agreed to, so read every line.

Make them sound like you

Ask one follow-up: "Make these sound like a small business owner who likes this client, not a bank." Then read each one out loud. Cut anything you'd never say.

When to pick up the phone

After the third email, a short, friendly call often works better than a fourth message. Sometimes the invoice went to the wrong person. Sometimes they're having a hard month. You'll learn more in two minutes than in another week of email.

For other customer emails you keep rewriting, here's how to draft customer emails and follow-ups with AI. Before you paste a real message into any chat tool, take the private details out first.

Under the hood

Generating the tiers together gives the model the whole ladder, so tier two reads firmer than tier one without jumping to tier three. Two constraints do the heavy lifting:

• Placeholder schema. Fixed bracket tokens keep personal data out of the prompt and make the output easy to fill later.
• Claim restriction. "Don't invent fees or policies" blocks a common failure: models add late fees and legal phrasing because that's what dunning emails often contain in their training data.

If your invoicing tool supports scheduled reminders, paste the approved text there. Otherwise, a calendar note on day 3, 10, and 21 is enough. Keep a human check before the firm tier goes out. Context the model can't see, like a client's known delay, changes what you should send.

Short close

Write all three reminders today: friendly, clear, firm. Use blanks, add only your real terms, and send each one on schedule. You're not being rude. You're being clear about work you already did.