put https://api-sandbox.coinflow.cash/api/merchant/payments//refund
Refunds a payment. First will check if the users wallet has credits to refund the payment. If so, will take the
credits from the users wallet and refund the payment. Otherwise, will transfer USDC from the merchants wallet to
Coinflow's wallet and refund the payment.The amount of USDC transferred will the total amount of the payment +
credit card fees + gas fees.