Why would changing a timing chain cause the radio to stop working ?

I had a timing chain replaced in my 05 Nissan Maxima.  All was well, until, I
noticed my radio/stereo was not playing.  Turned around, and Took it back
into the shop, and they
said they had no idea why. Was I sure it was working?  YES! Im SURE it was.  
Could someone PLEASE help me. It cost 4000.00
for the timing chain replacement at dealer, just to pick it up and have no radio.  
The volume shows, the CD load and unload, but the only lights on is the
volume, it has no sound either.  Undid the battery again, but that didn't work.  
Any ideas?  
I now hear a ticking sound when volume is turned up, it is inside passenger
floor board area......