Systems and methods are provided to process transactions initiated by users of mobile devices. In one aspect, a system includes a data storage facility to store phone numbers of users, and an interchange coupled with the data storage facility. The interchange includes a common format processor and a plurality of converters to interface with a plurality of different controllers of mobile communications. The converters are configured to communicate with the common format processor in a common format and to communicate with the controllers in different formats. The interchange uses the converters to transmit at least one premium message to a mobile phone at a first telephone number to provide an amount to the mobile phone using funds associated with a second telephone number, in response to a request initiated from a mobile phone at the second telephone number.