post https://sandbox.trustly.one/api/v1/transactions//refund
Refunds a previously completed Capture or Instant transaction (minimum of 0.99). You can optionally refund partially. You can do so as many times as you wish until the entire collected amount has been refunded.
A Capture or Pay transaction can only be refunded after the bank money collection has been processed and completed.
Ensure you also implement an Event Notification Handler to get transaction status updates.