mercedes slk 320 My radio and cd player has no power getting to them. I con?

My car was taken in for recall brake lights now I cant get power to my radio or cd player. I had to jump start my car because it hasn't been used. Once the car started it had power because it stated insert code I took it to the dealer and ask for them to put the code in for me since they had to fix recall. They called me said no power was getting to the radio and cd player so they couldn;t set the code. What do I need to check and what could of happen? Please let me know thanks Gracy Mitchell