Update an existing payment.
Payment status lifecycle is as follows:
PENDING: The initial status of an ACH payment put towards a Credit Key order.
CANCELED: Cancels an order installment payment that's currently in PENDING status.
RETURNED: This means the ACH payment was returned in some kind of failure state. i.e. NSF, Unauthorized Bank Account.
PAID: The ACH payment completed successfully.
REFUNDED: The funds for a PAID payment were sent back to the payer.