Jaguar X-Type (BJ2001): What to do to use telephone function?

Hello, an acquaintance bought a Jaguar X-Type built in 2001. The car has in the center console directly a block for the telephone function (different keys like dialing, phone book etc.). When you press the phone button, “No phone found”. He was at a Jaguar dealer, but he also had not had such a proper idea, he meant there come external people to check that and retrofit it himself he does only bodywork…!? He looked into the PC after the F ahrgestellnummer and meant it is all already retrofitted, there is only one module for the Simkarte missing. What does it cost he didn’t know either… So I wanted to ask here: what do you need to be able to call in the car or where is it retrofitted (glove compartment or center console etc.?) and what would that cost about? I am grateful about every tip 🙂 MfG Andy