A method comprising: receiving at a telecommunication service provider system a user request from a mobile device to activate a mobile user account and to activate one or more virtual private branch exchange services in accordance with configuration data, wherein data representing the request to activate one or more virtual private branch exchange services includes user identification information (218a; 218b); and wherein the configuration data is stored on the telecommunication service provider system and wherein the configuration data is pre-configured to provide the one or more virtual private branch exchange services; configuring at the telecommunication service provider system the one or more virtual private branch exchange services based on the configuration data; provisioning at the telecommunication service provider system a mobile user account associated with the mobile device with the one or more configured virtual private branch exchange services without requiring other information than the user identification information (218a; 218b), wherein activating the mobile user account includes associating the user identification information (218a; 218b) and an identifier for accessing the one or more virtual private branch exchange services with the one or more virtual private branch exchange services; and testing and validating by the telecommunication service provider system a successful activation of the one or more virtual private branch exchange services including generating a call to the mobile device using the identifier for accessing the one or more virtual private branch exchange services. receiving at a telecommunication service provider system a user request from a mobile device to activate a mobile user account and to activate one or more virtual private branch exchange services in accordance with configuration data, wherein data representing the request to activate one or more virtual private branch exchange services includes user identification information (218a; 218b); and wherein the configuration data is stored on the telecommunication service provider system and wherein the configuration data is pre-configured to provide the one or more virtual private branch exchange services; configuring at the telecommunication service provider system the one or more virtual private branch exchange services based on the configuration data; provisioning at the telecommunication service provider system a mobile user account associated with the mobile device with the one or more configured virtual private branch exchange services without requiring other information than the user identification information (218a; 218b), wherein activating the mobile user account includes associating the user identification information (218a; 218b) and an identifier for accessing the one or more virtual private branch exchange services with the one or more virtual private branch exchange services; and testing and validating by the telecommunication service provider system a successful activation of the one or more virtual private branch exchange services including generating a call to the mobile device using the identifier for accessing the one or more virtual private branch exchange services.