ZAMBO.

Direct answer

Late, they say. Short, they pay. Settle both from the timeline.

The work landed, and then the message: it arrived late, so the client is cutting the price. Maybe the delivery genuinely slipped. Maybe the date moved in a call nobody wrote down, or the project sat waiting on the client for two of the weeks now being counted against you. Arguing from memory loses, because the side with a timeline wins this conversation and memory is not one. Rebuild the timeline from the record, sort the days into whose they were, own the days that are honestly yours, and answer the cut line by line. Here is the method, step by step.

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Updated October 28, 2026. First published October 28, 2026. The two delivery records quoted below are real and public, with their client decision states read back from the live service.

Step 1. Stop arguing the date and build the timeline instead

A late-delivery cut is decided by five dates, and only five: the delivery date agreed at the start, any revised date agreed in writing along the way, the days the work sat waiting on the client for inputs, feedback, or a decision, the actual delivery date, and the acceptance date. Lay them out in one short table before you reply to anything. If the agreed date was never written down, say so honestly in your own notes and build the timeline from what does exist: messages, file dates, staged deliveries, the acceptance. A timeline with two gaps still beats a confident memory with none, and building it first stops you conceding days in the reply that the record would have given back to you.

Step 2. Sort the delay into whose days they were

With the timeline in front of you, the delay, if there is one, sorts into three piles. Your days: the work genuinely took longer on your side, estimates missed, other jobs crowded in. Own these plainly; they are the only days a lateness conversation can honestly touch. Client days: the project waited on their inputs, their review, their missing decision, and the delivery date moved day for day while it waited, whether or not anyone said that sentence out loud at the time. Shared or outside days: the tool that went down, the third party who shipped late, the change of scope both sides agreed would take longer. Each pile gets different treatment in the reply, and the sort is the reply: most late claims collapse by half the moment client days are dated and listed, because the client was counting calendar time and the timeline counts responsibility.

Step 3. Read the two states a delivery can sit in when the claim arrives

The timeline's last two dates, delivery and acceptance, are strongest when they live on a record the client already acted on. The record format is AER-1, published as an IETF Internet-Draft (draft-zambo-aer1-26), and each step carries a verifiable receipt: a receipt proves the saved result was not changed since it was saved. The two public records below show the states a delivery can carry:

Accepted: the decision is on the record

Pending: checked, and still waiting on a decision

An accepted record, 4 of 4 steps checked, decided_by client, release_hint ok_to_release, decided 2026-10-16T14:31:51.146Z in that example, carries its delivery sequence as dated steps with the client's own decision at the end: a lateness claim against it has to argue with the client's own dated acceptance. A pending record, 5 of 5 steps checked and release_hint hold, is delivered, checked work still waiting for a decision, which also matters here: a client who sat on acceptance cannot easily count their own decision time as your lateness. Know which state your delivery is in before the discount conversation starts.

Step 4. Answer the cut in order: timeline, piles, the number

Reply once, completely, in that order. First, the timeline table, five dates, no commentary. Second, the piles in one line each: the project waited on inputs for this many dated days, the agreed scope change added this many, the remaining slip of this many days is mine and I own it. Third, the number: the invoice stands in full where the delay was waiting time and agreed change, or here is the exact concession the honest slip earns, if your agreement names one or if you choose to offer one, stated as a figure, not a percentage pulled from the air to end the call. What not to do: do not accept an arbitrary cut as the price of getting paid at all. A cut accepted without the timeline teaches that every future invoice opens with a negotiation the client starts by naming a grievance.

Step 5. If a lateness term exists in your agreement, follow it exactly

Some agreements price lateness in advance: a stated reduction per week, a bonus for early delivery, a date after which either side may walk away. If yours does, the conversation is arithmetic, not advocacy: run the term against the timeline, client days excluded the way the term and the waiting record support, and send the worked figure. If no term exists, a client inventing one after delivery is rewriting the deal at the moment it favors them, and your reply can say exactly that, politely, with the timeline attached: the agreement priced the work and named the date; it did not price a deduction, so the invoice stands, and here is the timeline showing the delivery against the revised dates we agreed as we went. Either way the timeline is the document doing the work. This page is general information, not legal advice, and a large amount or a contract with real penalty clauses is worth a short professional review.

Step 6. Prevent the next one: dates and waiting on the same record as the work

The cheap fix is structural: keep the delivery date, every agreed revision of it, and every waiting period on the same running record as the work itself. The date is agreed where the stage is accepted. A client delay is logged the day it starts, with the missing item named, and the date moves day for day on the record where the client can see it move, not in a claim reconstructed at the end. Staged acceptances along the way give the timeline its middle dates, so no delivery is ever a single disputed afternoon again. Do that for one project and the late conversation, if it comes at all, lasts one message: the timeline is already built, already shared, and already decided on.

What a record does not settle

A verifiable receipt proves the saved result was not changed since it was saved; it does not prove a delivery met its date by itself, does not decide whose delay a day was, and cannot make a client pay in full. The agreed dates in writing, the dated waiting record, the delivery and acceptance on that record, and any lateness term you both signed are what the conversation stands on. This page is general information, not legal advice.

Frequently asked questions

My client says I delivered the work late so they will not pay the full amount. What do I do?

Do not argue the date from memory and do not accept the cut to get paid. Build the timeline first: the delivery date agreed at the start, any revised date agreed in writing, the dated days the project waited on the client for inputs or decisions, the actual delivery date, and the acceptance date. Sort the delay into your days, client days, and shared or outside days. Own your days plainly, list the client days with their dates, and then answer the number: the invoice stands in full where the counted delay was waiting time or agreed change, and any concession is the exact figure your agreement's lateness term produces, or a deliberate figure you choose, never an arbitrary cut named under pressure. Send the timeline, the piles, and the number in one complete reply. Most late claims shrink on contact with a dated timeline, because they were counted in calendar time and the timeline counts responsibility.

How do I prove when I actually delivered the work?

From the delivery record, not from a file's timestamp alone: the staged deliveries with their dates, the delivery message or handover that carried the final work, and the client's acceptance with its date are the chain a reviewer trusts. A handover the client opened and accepted is the strongest single item, because the date and the decider are on it. Screenshots and memory support that chain; they do not replace it. If the delivery truly has no dated record, build the honest version from what exists, messages, exports, version history, and say which links are missing rather than dressing the reconstruction up as a record it is not.

The delay was mostly the client waiting to send me what I needed. How do I show that?

Date the waiting the way the timeline needs it: each period where the next step was blocked on the client, what was missing, when you asked for it in writing, and when it arrived. Listed that way, waiting time stops being your excuse and becomes the client's own dated entries in the shared timeline, and the delivery date moves day for day across those periods on any fair reading. For the job still running, log the wait the day it starts and name the missing item on the record the client can see; a waiting period announced at its start is a fact, while the same period claimed at the end is an argument.

Should I accept a small discount for lateness just to close this and get paid?

Only as a priced decision, never as a ransom. If part of the slip is honestly yours and a discount buys a fast, full, final payment plus a client worth keeping, a stated figure with the timeline attached can be worth it, framed as your concession for your days, in writing, settling the invoice in full. What not to accept is a cut sized by the client's annoyance with no timeline under it: that version does not close the question, it prices the tactic, and the next invoice gets the same treatment with a different grievance. The timeline comes first either way, so any discount you give is visibly for the days that were yours.

How do I keep delivery dates and waiting time on the record for the next job?

Run each stage so the record carries the schedule with the work: the agreed date accepted with the stage, every revision of it accepted in writing, waiting periods logged the day they start with the missing item named, and the delivery closing as a handover the client accepts. When the work runs through Zambo, every step carries a verifiable receipt under AER-1, published as IETF Internet-Draft draft-zambo-aer1-26, so the steps, their dates, and the acceptance state sit on one record both sides can reopen. New users get 20 free calls per day, then they upgrade when the job needs more. For $0.99, run the next dated delivery that way and let the timeline build itself while the work runs: get the Day Pass. A Day Pass covers 24 hours, no subscription. Ongoing use is the Zambo Pass at $29 a month or $290 a year, and $19 a month for $ZAMBO holders, which adds private handover links, your branding, and the approval record as PDF and JSON files.

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