An unpaid invoice does not age like paper. It ages like produce. The longer it sits, the harder it is to collect, and the email you send at each stage decides whether it moves or keeps rotting.
I did accounts receivable work for years, chasing real invoices for real businesses, and the pattern was consistent: people send the wrong email for the age of the debt. They send a timid nudge at 90 days, or a legal threat at 30. Both fail, because the situation at 30 days and the situation at 90 days are different problems that happen to share an invoice number.
Here is what to send at each stage, and why.
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Open Table of contents
First, know which problem you have
If the invoice belongs to an active client and is a few days past due, that is not collections. That is routine follow-up inside a working relationship, and it runs on a gentler sequence tied to your service agreement.
This article is about the other problem: an invoice that has gone quiet for 30 days or more, often from a client you are no longer working with. Different situation, different tone, different emails.
30 days past due: assume nothing went wrong on purpose
At 30 days, the most likely explanation is boring. The invoice fell through a crack. An approver went on leave. The email got buried. Your job is to make paying easy and to give the client an honest way back that costs them no face.
Attach the invoice again so there is nothing for them to hunt for, and write something like this:
Subject: Invoice [number], following up
Hi [name],
I hope things are going well at [company]. I am following up on invoice [number] for [amount], which was due on [date] and is still showing as open on my end. I have attached it again so it is easy to find.
If payment has already been sent, let me know the date and I will match it against my records. If not, could you let me know when I can expect it? Happy to resend it to a different email or in whatever format your process needs.
Thanks, [Your name]
Notice what is not in it. No apology, because “sorry to bother you” teaches the client that your invoice is a bother. No pressure, because pressure at 30 days burns goodwill on what is usually a missed email. Warm, brief, and genuinely assuming the best. A client who was simply busy pays a friendly nudge faster than a stiff one.
60 days past due: stop pretending, and make yes easy
At 60 days, a soft nudge has already failed once, so the pretending stops. Name the age of the debt plainly: this invoice is now 60 days past due. Then do the thing most people forget, which is to make saying yes a small decision instead of a big one.
Offer a specific way to close it. A payment date this week. A two-part split, half now and half on a named date. Anything that turns “I owe money I have been avoiding” into “I click one thing and this is handled.”
One rule holds the whole stage together: negotiate the calendar, never the amount. The moment you discount an aged invoice, you have taught every future client what happens when they wait. The amount is not the problem. The decision to act is, so remove the friction around acting.
90 days past due: the final notice
At 90 days you are writing a record, not a relationship. The email is short and flat. It states the amount, the original due date, and the follow-ups already sent. It names a final payment date, and it says specifically what happens after that date, whether that is a collections agency, small claims, or writing the debt off and closing the account. Then you do exactly that.
No anger, no long paragraphs. Drama weakens a final notice. What gives it weight is that everything in it is verifiably true and that you follow through.
The part that makes all of this work: seeing the age
None of these emails get sent if you do not know the invoice is aging. That sounds obvious, and it is still the most common failure I saw. Solo business owners hold their receivables in their heads, and heads do not send reminders.
The fix is a simple invoice log with a days-past-due column and age buckets at 30, 60, and 90, so that every Monday you can see at a glance which stage each open invoice has reached. The stage tells you which email to send. The system does the remembering.
The scripts, done for you
I wrote the complete version of this system as ready-to-use documents: the full three-stage recovery script pack with email and chat versions for each stage, tone notes, and a worked example carried through all three stages, plus a revenue tracking spreadsheet that calculates days past due and age buckets automatically.
Both are part of the VA Business Owner Full System, twenty-one documents for running a VA business end to end, $39, delivered as Google Docs and Sheets you copy and edit.
And if your late invoice is from an active client rather than an aged account, the gentler in-engagement sequence lives in the VA Business Operations Pack alongside the service agreement it enforces.