Sorry to hear of your problem. Even worse, there is no simple answer
to your problem. Whether its a dealer, or an independent, is pretty much a gamble, as both can be either stellar, or totally incompetent. You need to ask around and find out who knows what they are doing in your area. That might be the dealer, or some hole in the wall dive shop. Now its possible that you might have had multiple problems, but you should have been informed of that possibility. Were the engine codes the same when you returned after your first repair? If they cant answer that, then the shop did not do their job. They should have detailed the specific codes, and what they did to remedy them, in detail. This is so that the next time the light comes on, they have a leg to stand on. If the codes are the same as they just repaired than they failed in the repair. If the codes are different then you know there is a new and different problem. Any time we diagnose and or repair a MIL/CEL we always attach a copy of the VAG print out to the repair order. If a customer comes back within a couple of days fuming because the light is back on, we hook the VAG up and scan for codes while he watches. If its the same code, we eat it. If it is different, then the customer knows hes getting the straight story, and he pays to correct the new problem.
What most people dont realize is that there are upwards of 100 malfunctions that will trigger a CEL/MIL. Next time you need to make sure you have the codes in hand that the shop just repaired. This way, you have your own leg to stand on. Ed