Invoice Follow Up: the sequence that runs without you, and what the unpaid invoice already cost you

An invoice follow up is the sequence of reminders that runs from the day you issue an invoice to the day it is paid. In South Africa two facts shape it: on the invoice basis you owe SARS the VAT before your customer pays you, and a debt prescribes after three years.

Most guides to invoice follow up are collections of polite email templates. Templates are the easy part. What decides whether you get paid is when the sequence starts, what it costs you to wait, and how long the law lets you wait before the debt stops existing. This post covers those three, with the sources.

The unpaid invoice has already cost you the VAT

This is the part almost no follow-up guide mentions, and it changes the arithmetic of waiting.

If you are a registered VAT vendor accounting on the invoice basis, which most vendors do, your output tax is triggered by the invoice, not by the payment. SARS sets this out in the VAT 404 Guide for Vendors (Issue 15) at section 4.2. The general time of supply rule is that a supply occurs at the earlier of two events: when an invoice is issued, or when any payment is received. The guide then states the consequence plainly:

"Vendors must therefore account for the full amount of output tax on any supplies made in the tax period, even where payment has not yet been received from the recipient."

Read that against a 90 day late invoice. You issued it, so the VAT fell due in that tax period. You paid it over to SARS out of your own cash. Your customer still has the money. You have financed both the work and the tax on the work.

There is one real exception, and it matters for smaller vendors: the payments basis. Vendors registered on the payments basis account for VAT when payment is actually received, so the problem above does not arise for them in the same way. The VAT 404 guide notes that supplies for a consideration of R100 000 or more still fall to be accounted for on the invoice basis even then. If you do not know which basis you are on, that is the first thing to check, because it determines whether a late invoice is a cash flow annoyance or a cash flow event.

Getting the VAT back is narrower than people assume

You can recover the VAT on a debt that goes bad, under the irrecoverable debts provision described at section 9.2 of the same guide. The conditions are specific:

1. There must have been a taxable supply for a consideration in money.
2. You must already have accounted for that supply in a VAT return.
3. The amount must be actually written off.

The adjustment is the tax fraction that applied at the time of supply, applied to the amount actually written off. The word doing the work is "written off". Deciding a debt looks doubtful, or raising a provision for it in your books, does not qualify. Until you write it off, the VAT stays paid.

And if the customer later pays after you have written the debt off, the guide is equally clear: you account for output tax on that payment in the tax period in which it is received. The relief is a timing correction, not a windfall.

The practical consequence for your follow-up sequence is that unpaid invoices are not neutral while they sit there. They have already moved cash out of your business, and the mechanism to get it back requires a formal decision you probably have not made.

How long can you chase an unpaid invoice in South Africa?

Three years, in the ordinary case, and then the debt is gone.

The Prescription Act 68 of 1969 sets the periods at section 11. Thirty years applies to debts secured by a mortgage bond, judgment debts and tax debts. Fifteen years covers certain debts owed to the State. Six years covers a debt arising from a bill of exchange, another negotiable instrument, or a notarial contract. Then section 11(d) catches everything else:

"save where an Act of Parliament provides otherwise, three years in respect of any other debt."

An ordinary trade invoice is an "other debt". Section 12(1) says prescription commences to run as soon as the debt is due, so the clock starts on your payment terms, not on the day you eventually get annoyed about it.

The clause that gives you the clock back

Section 14 is the one worth knowing, because it turns a follow-up email into something with legal effect:

"The running of prescription shall be interrupted by an express or tacit acknowledgement of liability by the debtor."

Section 14(2) then says prescription commences to run afresh from the day the interruption takes place. So a customer replying "yes, we owe it, we are short this month" restarts a three year clock. A customer saying nothing at all does not.

This is a real argument for a follow-up sequence that asks for a reply rather than one that just fires reminders into a void. A response that acknowledges the debt is worth more than a reminder that gets read. It is also an argument for keeping the replies, because the acknowledgement is only useful if you can produce it.

The sequence itself

Structure beats wording. A sequence that runs on fixed triggers will outperform a better-written one that runs when somebody remembers.

1. On issue. Confirm receipt and confirm the terms. This is also where invoice defects surface, and a defective invoice is the most common reason a payment run skips you. Our guide to tax invoice requirements in South Africa covers what must appear on the document, and invoicing for small business covers the rest.
2. Seven days before due. A short note that the invoice falls due shortly. Not a chase. This one exists to catch the invoice that never reached the right inbox, which you would otherwise only discover after the due date.
3. On the due date. A statement of what is outstanding, with the reference the customer's accounts payable system needs.
4. Seven days late. Ask a question rather than making a statement. "Is this invoice approved for payment, and if not what is outstanding on it" invites the reply that tells you whether you have a cash flow problem or a paperwork problem. It also invites the acknowledgement that matters under section 14.
5. Thirty days late. A call, from a person, with the invoice in front of them. By this point email has told you what it is going to tell you.
6. Sixty days and beyond. A decision, not another reminder. Escalate, agree a payment arrangement in writing, or start the process of writing it off. Each of those is an action. Sending a seventh reminder is not.

The step most businesses skip is the first one. The step most businesses repeat forever is the last one.

How to automate invoice follow up

The reason follow up decays is not that owners do not care about getting paid. It is that the sequence lives in somebody's memory and competes with billable work every single day. Automating it is mostly about moving four things out of a person's head.

What gets captured once. The invoice date, the terms, the reference the customer requires, and the name of the person who actually approves payment on their side. That last field is the one nobody records and everybody re-establishes by asking, every time, on every invoice.

What stops being re-keyed. If the invoice already exists in your accounting system, the follow-up sequence should read from it rather than being retyped into an email. Re-typing is where the wrong amount and the wrong reference come from, and a wrong reference is an invoice that will not be matched at the other end. We covered where this typing time actually goes in the real cost of manual admin for South African SMEs.

Where the reminder comes from. The due date on the record, not a person's diary. This is the whole point. A sequence triggered by the invoice itself runs on the invoice that was issued while you were on leave, and on the one issued the week everything went wrong.

What gets escalated rather than repeated. A rule that says a third unanswered reminder becomes a task for a human, instead of a fourth unanswered reminder. Automation is good at the reminders and bad at the judgment. Hand it the reminders and keep the judgment.

The upstream half of this, getting from quote to invoice without re-typing anything, is covered in how to automate your invoicing process. Follow up is the downstream half of the same pipeline, and it works far better when the invoice was generated from the quote rather than rebuilt by hand. Where the money lands afterwards is a related question, and tracking business expenses for SARS covers the record keeping side.

What automation will not do is decide how hard to push a customer you want to keep. That is a relationship call and it should stay with you.

Frequently Asked Questions

How long can you legally chase an unpaid invoice in South Africa?

Three years for an ordinary trade debt, under section 11(d) of the Prescription Act 68 of 1969. The clock starts when the debt becomes due, per section 12(1). After that the debt is extinguished and you cannot enforce it.

Does sending a reminder stop an invoice from prescribing?

No. Under section 14 of the Prescription Act it is the debtor's express or tacit acknowledgement of liability that interrupts prescription, not your reminder. When they acknowledge the debt, the three year period starts running afresh from that day.

Do I owe SARS VAT on an invoice my customer has not paid?

On the invoice basis, yes. The SARS VAT 404 Guide confirms that output tax is accounted for in the tax period the invoice is issued, even where payment has not been received. Vendors on the payments basis account when payment arrives instead.

Can I claim the VAT back on an invoice that is never paid?

Only once the amount is actually written off as irrecoverable. A doubtful debt provision does not qualify. If the customer later pays, you account for output tax on that payment in the period you receive it.

How many follow-up emails should an invoice get?

Enough to establish whether the problem is paperwork or cash, then a decision. In practice that is one before due, one on the due date, and two after. Beyond that, repeated reminders are a substitute for escalating, not a step toward payment.

Sources

• Prescription Act 68 of 1969, sections 11, 12 and 14. Read directly from the Act, 14 August 2026.
• SARS, VAT 404 Guide for Vendors, Issue 15, section 4.2 (accounting basis and general time of supply rule) and section 9.2 (irrecoverable debts). Read directly, 14 August 2026.

Every statutory reference above was checked against the primary document on the date of publication rather than taken from secondary commentary. Legislation and SARS guidance change, so verify against the current version before acting on it. This is general information, not tax or legal advice for your specific circumstances.

Where this usually goes wrong

In most businesses the follow-up sequence is not missing, it is inconsistent. It runs during a quiet week and stops during a busy one, which is exactly backwards, because the busy weeks are the ones generating the invoices. If you want to see where your own quote-to-cash process actually leaks, a business autopsy maps it end to end and shows you which steps are worth automating and which are fine as they are. You can also book a discovery call and talk it through first.