Associating a user service with a telephony identifier

A method of associating a user service, which is accessible by a user of a telephony device via an application on the telephony device, with a telephony identifier, the telephony device being operable in a radio telephony network, RTN, and being contactable via the telephony identifier when operating in the RTN, the method being performed by network equipment and comprising:

• communicating, between the network equipment and the application on the telephony device, first data comprising a communicated token;
• receiving, from the telephony device, second data comprising a received token, wherein the second data is received from the telephony device via an RTN-native service;
• receiving, from a network node in the RTN, the telephony identifier in control signalling associated with the RTN-native service;
• and
• based at least on correlating the received token with the communicated token, associating the received telephony identifier with the user service,
• wherein the application on the telephony device does not have permission to access information in incoming Short Message Service, SMS, messages received by the telephony device.