A method and system for processing a credit request from a credit/charge cardholder which automatically applies a rules-based decision process to determine whether to credit the cardholder's account, the amount of the credit, whether to do a chargeback to the merchant, and the amount of the chargeback. Individual issuing banks who issue credit/charge cards and individual merchants may specify custom rules which must be considered before a credit is issued and/or before a chargeback to the merchant is performed. The rules set forth the conditions under which the merchant will waive its right to prove the disputed transaction such that a chargeback is automatically issued to the merchant. For example, a merchant may specify that if the transaction is $20 or less, it will accept an automatic chargeback without the merchant's involvement and if the transaction is greater than $20, the merchant wants to receive notice of the dispute and the opportunity to prove or verify the authenticity of the transaction. In one aspect, the system may optionally include the blocking of calls based upon a list of potential callers from whom further transactions or requests for chargeback will be declined. The callers ANI or calling number identification is compared against the list, and the calls are not answered by the system.