no voice comand & no cd changer

[guysmalley]

Hi, this is my first post, thank you in advance for any help you may offer.
I purchase a 2000 e320 wagon 4matic from a friend. It is in great shape and brought it to a MB service center for a ec light which wouldn't go out. when I picked up the car the phone voice comand & cd changer didn't work. They said they didn't do anything to it and since the Nav system is a ero mb model they can't read two codes that come up ( the phone & cd was installed by MB but the nav was not, all worked fine till they worked on the car, I think they cancel out the codes for the ec and the comand at the same time, now I am stuck the radio works , the single cd works, the nav works it is just the voice & cd changer that doesn't. Anybody have any thoughts? help
-guy smalley