The application's payment is unapplied by exactly that application (POST /v1/payments/:id/unapply with applicationIds [id]): the order and invoice it paid roll back by its amount. An application that issued a customer credit is refused (409 issued_credit). 404 when no application of this tenant has the id, or its payment is outside the caller's channels. version is the payment's.

Scope: payments:write, channel:write or admin. A permission group made before the Channel API scopes existed grants it as payments:manage.

Idempotency: send Idempotency-Key; a retry with the same key replays the first answer.

Rate limit: write class, 1,200 requests per minute per tenant by default (read class 6,000). Every response carries X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset; a refusal is 429 rate_limited with Retry-After.