Reason Codes 76 (used by Visa) and 4850 (MasterCard) designate chargebacks resulting when a credit is posted on a cardholder's account as a purchase....
Chargeback Reason Codes 73 and 4835 are issued when two conditions were met: a payment is made with an expired card and the transaction is not authorized....
Merchants should monitor their average transaction amount and count in each credit card batch and alert their processor if either is substantially exceeded....