A system for customizing a profile of a subscriber having access to a service platform, the profile configured to comprise subscriber profile data, and the service platform maintaining the profile for the subscriber, the service platform comprising: a database module for storing subscriber profile data; service platform means for verifying that a subscriber has legitimate access to a subscriber service manager based on information provided by the subscriber; the subscriber service manager configured to, if the subscriber is verified to have legitimate access, receive a subscriber request for a transaction identifier at the service platform, the subscriber service manager, responsive to receiving the subscriber request for a transaction identifier, being configured to generate (336, 340) a transaction identifier, to store (334, 356) a copy of the transaction identifier, and to communicate the transaction identifier to the subscriber; and a customization module configured to receive and process a customization message sent to the system from the subscriber, the received customization message including new subscriber profile data or customized subscriber profile data and a transaction identifier; the customization module, responsive to receipt of the customization message, being configured to compare the transaction identifier in the received customization message with the copy of the transaction identifier stored by the subscriber service manager, and to register the new subscriber profile data to the subscriber profile in the database module or to update previously stored subscriber profile data in the database module with the customized subscriber profile data when the transaction identifier in the received customization message and the copy of the transaction identifier stored by the subscriber service manager correspond. a database module for storing subscriber profile data; service platform means for verifying that a subscriber has legitimate access to a subscriber service manager based on information provided by the subscriber; the subscriber service manager configured to, if the subscriber is verified to have legitimate access, receive a subscriber request for a transaction identifier at the service platform, the subscriber service manager, responsive to receiving the subscriber request for a transaction identifier, being configured to generate (336, 340) a transaction identifier, to store (334, 356) a copy of the transaction identifier, and to communicate the transaction identifier to the subscriber; and a customization module configured to receive and process a customization message sent to the system from the subscriber, the received customization message including new subscriber profile data or customized subscriber profile data and a transaction identifier; the customization module, responsive to receipt of the customization message, being configured to compare the transaction identifier in the received customization message with the copy of the transaction identifier stored by the subscriber service manager, and to register the new subscriber profile data to the subscriber profile in the database module or to update previously stored subscriber profile data in the database module with the customized subscriber profile data when the transaction identifier in the received customization message and the copy of the transaction identifier stored by the subscriber service manager correspond.