Since Payrailz uses a Good Funds model, payments won't get sent out unless Payrailz receives an “Authorized” response from OCU's core-direct file. This means that “Insufficient Funds” will not be debited, and Payrailz won’t send the payment out.
If an electronic payment is rejected, the funds are returned to OCU to debit the member's account. This is done in an automated fashion as part of the nightly batch process.