A chargeback is a mechanism created to solve those charges made to a credit or debit card that are not recognized. It is a way to protect the cardholder from charges made without their consent.
It is generated when a cardholder contacts their bank directly to notify that they do not recognize a charge made to their credit or debit card by your business. At that point, the cardholder's issuing bank sends the chargeback request to the merchant's bank.