Here is a list of all players and their roles within a chargeback process:
Buyer: this is the person who first submits a chargeback request to their issuing bank; starts the whole process with a transaction dispute.
Merchant: seller of the goods and/or services and who must fight or accept the chargeback.
Issuer: the bank to which the buyer's credit card is connected and used to purchase the item or service.
Acquirer: a financial institution that obtains the rights to the merchant's account and is tasked with receiving payment on behalf of the merchant. In this case, PagueloFacil.
Credit Card Company (The Brands): the organization that oversees the process. In some cases their procedures differ from each other (Visa, Mastercard, etc.).