post https://snaprefund.io/api/v1/payments/setFeePayer/
Set the fee payer for a given payment method. For example, when a sender is set as the fee payer for ACH transactions, if a $10 payment is sent with an ACH fee of $1 then the sender will be charged $11 and the recipient will receive the full $10. The fee payer can be set on a per payment rail basis, so even in this example where the sender pays fees for ACH transactions, the recipient can still be set to pay the fees for an instant or paper check transactions.