Bancontact Pro Payment Refund Service API
First-party OpenAPI 3.1 contract (v3.0.3) for creating and retrieving refunds against SUCCEEDED Bancontact Pro payments. Refund creation is idempotent on a required Idempotency-Key header, must be activated per merchant by Bancontact support, and is secured with an ES256 detached JWS request signature; refunds are deducted from the merchant's next bulk payout.