Novel features to be used in a proxy card payment system include a real-time request to override a declined transaction or to select a different financial account and the insertion of user identification information into the transaction approval message sent to the merchant. A payment request is forwarded to the payment system, which maintains the proxy card account and determines whether the transaction violates a user-defined rule. If the transaction is declined by the issuer that maintains the financial account, or the payment system for violation of a user-defined rule, the payment system sends a real-time message to the user. The user is prompted to override the rule causing the transaction to be declined or to select a new account to process the transaction. Once the payment system receives authorization for the transaction, it inserts the user identification information in an approval message before transmitting the approval to the merchant.