Guide · For businesses

Letter of demand for an unpaid invoice

Chasing a client who won't pay is the least enjoyable part of running a business. A well-drafted letter of demand is the step that turns "I'll get to it" into payment — and sets you up to recover the debt in court if it doesn't.

Updated August 2026·6 min read·By LetterUp

Why a letter of demand, not another reminder

A statement reminder is easy to ignore because it carries no consequence. A letter of demand changes the register: it's a formal document, it references the debt precisely, it sets a hard deadline, and it makes clear that court action follows if the deadline passes. For most late payers, that shift alone is enough — paying you becomes cheaper and simpler than the alternative.

What to include

  • Your business details and the debtor's correct legal name (the entity on the invoice).
  • The invoice number(s), date(s) and the amount outstanding.
  • A brief reference to the agreement or purchase order the work was done under.
  • A clear demand for the full amount, plus any interest.
  • A firm deadline — commonly 7 or 10 business days.
  • Your banking details for payment, and a statement that you'll institute legal action if unpaid.

Interest you can claim

The rules on your side Where your terms provide for interest on overdue accounts, you can claim it as agreed. Even without such a term, the Prescribed Rate of Interest Act 55 of 1975 generally entitles you to interest on an overdue debt from the date it fell due. Stating this in the letter shows the debtor the cost of delay is growing.

Prescription: don't let the clock run out

Under the Prescription Act 68 of 1969, most ordinary trade debts prescribe after three years — after which you can lose the right to claim entirely. The clock generally runs from when the debt became due. Sending your letter of demand promptly, and issuing summons before the three years expire if it comes to that, protects your claim. Don't let an awkward client run the clock down.

Draft it in two minutes

Enter the invoice details and LetterUp produces a professional letter of demand, ready to send as a PDF — for R79, no account needed.

Write a demand letter →

Escalating to court

If the deadline passes, your route depends on the amount:

  • Small Claims Court — for amounts up to the prescribed limit. It's fast, cheap and you don't use an attorney. You must first send a letter of demand and allow 14 days before issuing a summons.
  • Magistrate's Court — for larger amounts within its monetary jurisdiction, usually with legal representation.
  • High Court — for substantial claims above the Magistrate's Court limit.

In each of these, your letter of demand is the first document the court will want to see.

Chasing invoices at scale

If late payment is a recurring drain — not a one-off — generating each letter by hand doesn't scale. The LetterUp business portal lets you produce demand letters on your own company letterhead, store customer details for one-click pre-fill, track what you've sent, and group overdue accounts into cases with automatic deadline reminders. Businesses start with three free letters, no card required.

Frequently asked questions

Can I charge interest on an overdue invoice?

Yes. Where your terms provide for interest, or under the Prescribed Rate of Interest Act, you can generally claim interest from the date the debt fell due. Say so in the demand for extra pressure.

How long do I have to recover an invoice?

Most trade debts prescribe after three years under the Prescription Act. Send a demand — and issue summons if needed — before that period expires to protect your claim.

What's the quickest way to recover a small invoice?

The Small Claims Court is fast and needs no attorney. Send a letter of demand and allow 14 days before issuing a summons.

Do I need a lawyer to send one?

No. Any business can send a letter of demand — it just needs the debt, the invoice, the amount and a deadline. LetterUp drafts one for R79, or generate them in bulk on your letterhead in the business portal.

LetterUp is a document preparation service, not a law firm. This guide is general information, not legal advice, and does not create an attorney-client relationship. For significant debts or contested claims, consult a qualified South African attorney.