A client claims I didn't do the work I billed for. How do I defend myself?
Defend from the record, line by line: send one document mapping each billed item to its job, its steps with their saved results, its delivery date, and the client's recorded acceptance where one exists. Review the receipt and actual deliverable before accepting a handover.
"You didn't do the work" is the most serious claim a client can make and, against recorded work, the easiest to answer, because the answer is not an argument. It is an index. The defence document is built by walking the invoice: for each line, the job; for each job, the handover; on the handover, the steps and their timestamps; and where the client accepted, their own recorded decision, which converts the defence from your word into their act.
Send it once, complete, in a level tone, and let it be the last long message in the thread. Broad claims thrive on exchanges; they wither under documents. If an item genuinely cannot be evidenced, say so in the document itself and deal with that item separately and honestly; one conceded line inside an evidenced document strengthens every other line, because the reader learns the document admits its edges.
Where the work was never recorded, the defence is the weaker set this file keeps naming honestly: files, messages, platform histories, assembled into the same itemised shape. Build it the same way, label its seams, and then change the default so the next invoice is defended by records made while the work ran, not by archaeology after it was billed.
Template: the line-by-line defence document
Header: invoice reference, amount, date, your one-paragraph summary. Table, one row per invoice line: Line | Job | Steps (numbers on the handover) | Delivered (date) | Accepted (date and decider, or "decision not recorded") | Record link. Closing lines: items you cannot evidence, named plainly with your proposed remedy; the total you stand behind; the next step you propose (payment, or the structured path from the refusal ladder in this cluster). Attach: the agreement and any change notes.
Worked example
Every row of that table resolves into an object like the public handover at https://zambo.dev/handover/45434a17-4afc-486a-9646-e689bcee4297 , whose steps and recorded client acceptance are readable by the claimant. A defence whose rows all open this way rarely needs a second document.
Frequently asked questions
Should I send the defence before or after the demand letter?
The defence answers the claim; the demand letter pursues the debt. Send the defence when the claim is made, then let the payment ladder proceed on its own dates. The two documents support each other and should not be merged into one emotional bundle.
The client accepted the work and still claims it was not done. How?
Then the acceptance record is the centre of the defence: their recorded decision, on the delivered steps, with its date. Claims that contradict the claimant's own recorded acts collapse quickly in any forum, including the informal one of their own finance team.
What if the claim is made publicly, in a review or a post?
Answer once, briefly, in the same place: state that the work is recorded and itemised, offer the record to any reviewer, and take the detail offline. Public arguments reward brevity and documentation, in that order.
By Brennan Zambo, founder of Zambo.
Last verified: 2026-10-17.
Try a handover
A handover gives your client one proof link with verifiable receipts to review, then Accept or Flag.
try it: say 'use zambo to hand this over to <client>' in your ai