The customer pays some invoices but never the disputed one

The scenario

This customer pays — but not everything. Newer invoices get settled on time, the account stays active and looks healthy at a glance, yet one older invoice is consistently skipped. Every statement still shows it outstanding, and every time you raise it the response is vague or it simply gets lost in the noise of the invoices that do get paid. Because money keeps arriving, the account never feels like a problem, and the one unpaid invoice quietly ages in the background. Left alone, that invoice will keep being passed over until it is old enough to be awkward to chase at all.

What's really going on

Cherry-picking is rarely random. A customer who pays newer invoices but skips a specific one is almost always doing it on purpose, and there are two common reasons. Either they have a genuine dispute about that particular invoice and have decided to handle it by simply not paying rather than raising it formally, or they are manufacturing a soft dispute to delay an amount they would prefer to avoid. By keeping the rest of the account current, they make the relationship look healthy and bank on you not wanting to rock the boat over one invoice. The pattern is the tell: consistent, selective non-payment of the same item is a decision, not an oversight, and treating it as an oversight is exactly what lets it persist.

Your options

The goal is to bring the skipped invoice out of the shadows and force it to a resolution:

• Allocate payments deliberately. Where your terms allow, apply incoming payments to the oldest invoice first so the disputed item cannot be perpetually skipped.
• Isolate and confront the invoice. Raise it as a specific, standalone item and ask directly whether there is a dispute.
• Resolve the underlying issue. If a genuine problem exists, deal with it head-on so the invoice can either be corrected or paid.
• Escalate the single item. Treat the unpaid invoice on its own merits, including formal steps, even while the rest of the account continues.

Recommended approach

Stop letting the invoice disappear into the general flow and pull it into the open. Ask the customer directly and specifically: this invoice remains unpaid while others have been settled — is there a problem with it? Forcing the question converts a comfortable avoidance into a choice between paying and articulating an actual dispute. If a genuine issue surfaces, resolve it properly — correct an error if you made one, or stand firm with evidence if the invoice is sound. If no real dispute exists and the skipping simply continues, escalate that single invoice on its own merits, applying your normal overdue process to it regardless of the otherwise current account. Where your terms permit, allocating new payments to the oldest balance first stops the customer indefinitely parking the item. The point is to deny the invoice the quiet corner it has been living in, because an unpaid invoice that is never directly confronted is one that quietly becomes a write-off.

What to avoid

Do not let the healthy-looking account lull you into ignoring the one invoice that is not being paid; a current account with a permanently skipped item is not actually healthy. Do not allow the disputed invoice to age indefinitely while you avoid an awkward conversation, since age only weakens your position. Do not allocate payments contrary to what your agreement or the customer's clear instruction allows — payment allocation must respect the terms. And do not assume bad faith without asking; sometimes there is a real, fixable problem, and the direct question is what surfaces it.