"A third party caused the problem"

The scenario

Something went wrong — a delay, a defect, a downstream failure — and the customer pins it on a third party: the courier, a subcontractor, another supplier, the manufacturer. On that basis they refuse to pay your invoice, even though your part of the deal was performed. The blame may be accurate, but it's often aimed in your direction to justify withholding payment.

The pivotal question is contractual: whose obligation are we talking about? If you performed your contract, a third party's failure elsewhere generally doesn't extinguish what's owed to you — the customer's remedy is against that third party, not in withholding your invoice.

What's really going on

There are genuinely different situations folded into this objection. The third party may be your responsibility — a subcontractor you engaged, a courier you chose — in which case their failure is effectively yours and you may need to remedy it. Or the third party may be nothing to do with you — the customer's own supplier or a party they selected — in which case it's their problem to pursue, not a reason to stiff your invoice.

The customer may not draw this distinction, especially if not paying is convenient. So the work is to identify the chain of responsibility: who engaged whom, whose contract covers the failed element, and whether your own obligation was met. That usually tells you whether the third-party point actually touches your invoice or merely deflects from it.

Your options

Trace the responsibility, then respond accordingly:

• Establish the chain. Work out who engaged the third party and whose contract covers the failed element.
• Own a third party you chose. If the failing party was yours — your sub, your courier — remedy the issue as your responsibility.
• Decline a deflection. If the third party was the customer's or unrelated to you, explain your contract stands and direct them to pursue the right party.
• Keep your invoice on track. Where your obligation was met, request payment regardless of the third-party grievance.

Recommended approach

Untangle the chain calmly: "Let's be clear about who's responsible for what. We delivered our part as agreed. The issue you're describing sits with [third party]." If that third party was genuinely yours — a subcontractor or carrier you engaged — own it and remedy the problem; that's your obligation and avoiding it would be unfair. If the third party was the customer's choice or otherwise nothing to do with you, explain courteously that your contract stands and their remedy lies with that party, not in withholding your payment.

Keep your own invoice moving where your part was performed: "Our work is complete and in order, so this invoice is payable — your claim against [third party] is a separate matter." Don't get drawn into adjudicating a dispute that isn't yours. Where responsibility is genuinely mixed or unclear, a fair, documented apportionment may be sensible. The anchor throughout is your contract and your obligation, which our dispute handling guidance keeps front and centre.

What to avoid

Don't accept blame for a third party that wasn't yours — absorbing someone else's failure to keep the peace costs you money you're owed. Don't dodge responsibility for a third party you genuinely chose, either; passing the buck on your own subcontractor or courier is both unfair and unconvincing. Avoid being pulled into refereeing a dispute between the customer and a party you have no contract with. And don't let your performed-and-payable invoice stall while the customer fights a battle that has nothing to do with what they owe you.