A customer paid only part of my invoice. What should I do?
Customer paid a partial amount — your options and the legal risk you need to know about
Short answer
If the partial payment was agreed in advance (installment plan), invoice the remaining balance per the schedule and follow up normally. If the customer paid less without agreement — especially if the check was marked 'payment in full' — do not cash it without explicitly reserving your right to the balance in writing. Cashing a 'payment in full' check can legally extinguish the rest of the debt in many US states under the doctrine of accord and satisfaction. Call within 24 hours, acknowledge receipt, and confirm what they say the partial covers.
The most dangerous scenario is a customer who mails a check marked 'payment in full' or 'full and final settlement' for less than they owe. Under common law accord and satisfaction doctrine — codified in UCC § 3-311 — cashing that check can constitute acceptance of the lesser amount as full discharge of the debt, especially when there is a genuine dispute about the balance. If you deposit the check without objecting in writing, you may have settled for less than you are owed.
The safe response: call or email within 24–48 hours of receiving the partial payment. Acknowledge that you received it. State explicitly that you are applying it as a partial payment toward invoice [number] and that the outstanding balance of [amount] remains due. Document that in writing. Some states require that you return the check (not cash it) to preserve your claim; others allow you to accept it while reserving rights in writing. If the amount is material, a brief conversation with a local attorney is worth it.
When the partial payment is not a dispute but a cash flow problem — the customer paid what they had — a payment plan conversion is usually the right move. Propose a schedule in writing: a fixed amount by a specific date, with late-fee accrual on the remainder. Most customers who reach out about a partial payment are trying to pay; they just cannot pay everything today. A written plan with a clear timeline converts a stalled receivable into a predictable one.
The dispute signal is a customer who holds back 10–15% citing work quality or scope disagreement. This is different from a cash flow partial pay. Do not accept the partial as final without resolving the scope issue — call and get the specific objection in writing. If the disputed amount is under a few hundred dollars and the customer is long-term, it is often worth crediting it to keep the relationship. If it is a recurring pattern, that is a different problem.
Document everything in this situation. Text messages, emails, and written agreements about the partial and the remaining balance are your protection if you eventually need small claims court or a demand letter. 'We discussed it on the phone' is hard to prove.