Mercedes W204 2012 - No sound and No navigation

My car is a Mercedes C250 CDI, 2012. 

Few weeks ago my my Navigation stopped working. It displays "No Navigation" message on display

Also i have No sound on speakers, though it finds radio stations on display.

I used Star tester and it showed me "telematic control module" fault permanently.

I don't know the location of this module.

Does anyone know where is located? 

I checked the trunk, but there i found only the amplifier, where can it bee that module.

Best regards,