It is disappointing to hear that your dealer has given up on this issue already, especially with a car that is still relatively new, so you may wish to escalate this to Peugeot UK customer services. In the meantime, the fact that both the live traffic and SOS functions have failed at the same time suggests there is an issue with the car's data connection, as both of these systems require a functioning and stable mobile connection to operate. You can try resetting the telematics system by holding down the assistance button and the red SOS button together for 10 seconds, and it would also be worth checking the connection status of the infotainment system - you can do this by going to the navigation's connection service menu for a connection status. You can also reboot the infotainment system by holding down the power icon for 20 seconds.

If this does not restore the connection it is possible that the back-up battery for the telematics system has failed which can cause the system to shut down, so this is something you can request the dealer to check, or an independent Peugeot specialist or automotive electrician if you are unhappy with the dealer's quality of service.