If you take it to them a third time and they can't fix it correctly you have grounds for the lemon law in most states. The cure for the problem is a new sunroof track, this requires removing the entire upper interior and headliner which isn't easy on an audi. Im guessing they are trying to stay away from that due to lack of experience or lazyness.
99 Chevy Silverado Z71 6" rough country lift/W 35" tires, 4.10 gears, (4.56 soon) S&B CAI and a flowmaster super 44 exhaust.
"Never argue with a fool, they will lower you to their level and beat you with experience." My personal motto.