Data Link Blues
 

I have a 2002 TT Roadster 225. At inspection in July the data link was working. But, at a subsequent service it was discovered there was no communication.
Since then my local foreign car service center has been going through various stages of diagnostics. Including rebooting all of the modules and visual inspections and using various programs to try to determine the problem. There are no indications of any electronic problems. Everything works fine . There hearts are in the right place, but I am starting to think they are trying to hard to solve this problem. Is it time to take it to "The Audi Dealer". I was told by another foreign car shop that it will probably be my best bet in getting this resolved being that they are more familiar and have the better diagnostic equipment.
Any advice would be helpful.
Thanks in advance