In order to issue a refund, log in to your Cardinity account and click Payments List in the Payments menu. Then type the payment ID or select the payment you need in the Payment ID column, and click the Refund button. You can issue a full or partial refund, depending on the situation.
Here you can find additional resources that may help you in the process and tell you more about payment processing.
If you haven't found answers to your questions here or need any further assistance, don't hesitate to contact us.