Abstract: A system for unified billing combining mobile telephone and credit card services, in one example embodiment comprises a communication module to receive, from a merchant, a request to process a transaction, the request including data related to a subscriber identity module (SIM), a customer identification module to identify, based on the data, a customer associated with the subscriber identity module (SIM), a credit verification module to ascertain information related to a credit account associated with the customer, a code generating module to selectively generate a security code to be sent to the subscriber identity module (SIM), the security code to be provided to the merchant in order to complete the transaction, a code verification module to receive and verify the security code sent by the merchant, and a transaction module to selectively complete the transaction based on the security code verification.