PhotoBiz Forms allow you to accept credit & debit card payments from your clients using the merchant you've configured. If you need to refund a payment to a client, you will need to process the refund from the merchant account you're using to process your credit/debit card payments.
Here are some helpful links to the merchants that can be used to accept Form payments:
Please Note: For account-specific questions with your merchant, you'll want to contact their support team as PhotoBiz has no access to your account details with a 3rd party service provider.