How to Follow Up on an Unpaid Invoice Without Losing the Client

Check your side first

Before you chase anyone, spend two minutes making sure the invoice can actually be paid. Most late invoices turn out to be a small problem on your end, and chasing a client for something you got wrong is a quick way to lose them.

• Did the client receive it? Check the email address or the number you sent it to.
• Is the due date clear, and is it written on the invoice?
• Are your bank details right, with a payment reference the client can copy?
• Does the client need a purchase order number on it before their accounts team will pay?

If any of those is off, fix it and resend. If you're not sure your invoices are clear enough, the six most common invoicing mistakes is a useful checklist.

A follow-up rhythm that stays polite

There's no official schedule, so this is a suggestion rather than a rule. The idea is to start friendly and get firmer only if you need to, and to put every step in writing so you have a record.

1. A day or two before the due date (optional): a short heads-up with the invoice attached. Good for clients who pay late out of forgetfulness.
2. The day after the due date: a friendly nudge.
3. About a week after: a clear message that asks for a payment date.
4. Two to three weeks after: a firm message that mentions any late fee or interest in your terms, and when you'll move to the next step.
5. A month or more after: a formal letter of demand (see below).

Many late invoices aren't refusals. The invoice got buried or passed to the wrong person, and a prompt, friendly message is often all it takes.

Messages you can copy

Keep the tone steady and factual. Don't guess at reasons, and don't write anything you'd be uncomfortable seeing read out later. WhatsApp is fine for the early nudges because clients see it quickly, but send the firmer ones by email as well so there's a clear written record.

Make it easy to pay

A client who wants to pay shouldn't have to hunt for your account number. Include the invoice link or PDF in every message, repeat the bank details and reference, and if they say they've paid, ask for proof of payment so you can match it. In Invo the client opens the invoice page, sees your banking details and the reference, and can upload proof of payment straight onto the invoice instead of into your chats. If you've connected your own payment gateway, they can also pay by card from the same page.

Late fees and interest

You can only charge a late fee or an agreed interest rate if your client agreed to it beforehand, which usually means it's in your quote, contract or invoice terms. Adding it after the fact is a good way to start an argument. Spell it out up front, for example "A late fee of X% a month applies to invoices unpaid after the due date", and apply it the same way for every client.

If you didn't agree a rate, the law still provides one called mora interest. It's set by the Prescribed Rate of Interest Act, tied to the Reserve Bank's repo rate plus 3.5%, so it changes. It's simple interest, not compound. Whether it runs from the due date or only from the date you make a formal demand can depend on your agreement, so the safest move is to put your terms in writing and send a clear demand. Look up the current rate before you quote a figure to anyone. Our post on common invoicing mistakes explains why having a clause beats relying on the default.

The letter of demand

When messages haven't worked, the next step is a letter of demand. It's a formal written request for payment, and it's also the first thing a court or the Small Claims Court will expect to see. A good one is short and covers:

• Who you are and who the client is
• The invoice number, the date, what it was for and the amount owed
• The date payment was due
• The date by which you now expect payment (7 to 14 days is a reasonable deadline)
• What you'll do if you aren't paid, such as claiming through a court
• Your banking details

Send it in a way you can prove, such as email with a delivery or read record, or registered post, and keep the proof. The Small Claims Court has its own prescribed letter of demand (Form 4), and you have to prove it was delivered.

Small Claims Court for unpaid invoices

For smaller debts, the Small Claims Court can be a cheap route. Since 1 August 2026 it hears claims up to R30,000 (it was R20,000). A few things to know:

• Only a natural person can bring a claim. If you trade as a sole proprietor, that's you. A company or close corporation can't be the one suing, although it can be the one sued.
• It's built to be used without lawyers. The clerk at the Magistrates' Court helps you complete and serve the papers.
• You'll need your invoice, your proof the work was done, your messages and the letter of demand.

Above R30,000, or if you trade through a company, you'd typically go through the Magistrates' Court or a lawyer instead. Either way, this is general information and not legal advice, so for a large or disputed debt it's worth a short consultation first.

Don't wait too long

An ordinary debt like an unpaid invoice generally prescribes three years after it becomes due, which means you lose the right to recover it. In practice, the odds of getting paid drop long before that, so follow up while the job is fresh in the client's mind.

Doing this in Invo

Invo shows which invoices are overdue and by how many days, so the ones you've forgotten rise to the top. Tap Remind and a polite message opens in WhatsApp or your email app with the invoice link already in it, and you press send. Reminders are on the Free plan, and the Solo plan adds late fees, which Invo puts on as their own line if you've set a monthly rate. Part payments leave the balance open, and anything a client overpays is held as credit on their account. The follow-up section of the features page shows how it works, and you can start free on the free plan.

It also helps to start earlier, with the invoice itself. Our guide to getting paid faster as a freelancer covers payment terms and deposits, how to create an invoice covers what to include, and if you're not VAT registered, here's how to invoice without VAT.

Questions people ask