AnswersWhen a client won't pay
Should I phone about a late invoice, and what do I say?
The short answer
Yes, once. Phone when your day-7 email has had no reply, and leave the call with three things: a date the money leaves their bank, a name and a reason. Then write it up within the hour, because a call leaves no record. A promise on the phone also does not restart the six-year time limit1 for a claim: only a payment or their acknowledgment of the debt2 does, and that must be in writing and signed by them3.
England and Wales only. WolfX is software, not a law firm.
What you can add
A £3,600 invoice, paid on the date they gave
Say your agency invoiced another business £3,600 for a month's work, due on 14 August 2026. Your day-7 email on 21 August gets no reply. You phone on 24 August and are told: the payment run on 4 September. If the money arrives that day, it is 21 days late.
Interest runs from 15 August at 11.75%, the rate for invoices that went late in the second half of 2026, and grows by £1.16 a day until they pay. Paid on their date, they still owe £94.34 in late payment sums, and your write-up has already named both.
The road ahead
Six steps. One call. All free.
Step 1: Email first, then phone
Phone once the invoice is late and your day-7 email has had no reply. Late means past the agreed date, or 30 days after they got it5 if you did not agree one. The law fixes none of these days. If they have asked for email only, use email.
Step 2: Ask for whoever approves payments
Start with the contact on the invoice, then ask for accounts payable. It is highly unlikely that the first, second or even third person you speak to is the person responsible4, so be pleasant and ask who is.
Step 3: Open with a question, not a complaint
Say you are going through the books and there appears to be a payment missing, and ask whether they can help. The Small Business Commissioner's advice4 is to be assertive, not aggressive. Have the invoice in front of you.
Step 4: Leave with a date, a name and a reason
A date is the day the money leaves their bank. "Soon", "this week" and "end of the month" are not dates. Ask who is dealing with it and how to reach them, and what is holding it up. Close with: "Can you confirm that by email today?"
Answers you will hear: "it's in the next payment run" (which day?), "I didn't get it" (give me an address and I'll send it now), "it's with approvals" (whose?), "I'll check and call back" (when?), "it's disputed" (what exactly, in writing?). Do not mention solicitors or court. That belongs in writing.
Step 5: Write it up within the hour
Send the email below to the person you spoke to, copying accounts. It records what was said, the date, the name and the reason, with interest at 8% over the base rate8 building: 11.75% a year9 for invoices that went late in the second half of 2026. If they don't correct it, yours is the only record.
Step 6: If the date passes, write again
You now hold their date in writing. If it passes, write the next morning with the interest worked out to that day, and see what to do when a client keeps promising. One more call rarely adds anything.
A letter you can copy
Write-up email after the call
Send it within the hour of the call, to the person you spoke to, with the accounts address copied in.
Tap a highlighted gap to see what goes in it.
Send it by email, to the person you spoke to and the accounts address, so it is dated and kept. Add it to your chase log. If they reply with the date, keep it. The law asks for an acknowledgment in writing and signed to restart the six years. Whether an email reply counts is a question for a solicitor who does debt recovery.
When not to bother
When it isn't worth it
- They have asked for email only. Use email. A call after that request ignores what they asked for.
- The invoice is disputed in writing. Answer in writing, so the dispute and your reply sit together. See what happens when a client disputes an invoice.
- The sum is small and the client is a good one. An email may do the job, and a call can cost more goodwill than the money is worth.
- They have promised three dates and missed three. Stop ringing and write. See what to do when a client keeps promising.
- The company is in administration or liquidation. The person you need is the office-holder, not accounts. See what to do when a client is in administration.
The Wolf's note
A call is gone the moment it ends. The email is what stays. Send it while the details are fresh, and let the date they gave do the work.
Mr. Wolf · the AI inside WolfX
What comes next
Your next move
My client has gone quiet. How do I get an answer?
Ask someone else: ring accounts payable, email a second name, then post to the registered office, which the law counts as delivery to the company.
6 min read · Letter included
How do I chase an overdue invoice politely?
Two short emails: on day 7, ask for a payment date; on day 14, name one, with the interest and fixed sum worked out.
5 min read · Letter included
Don't want to do this yourself?
The Wolf does every step for you. He works out the sums, writes the letters and keeps track of every date. Nothing goes without your yes.