Custom Tuning, Faster to Slower

I need some expert advice. I just recently had my 2003 TT 225 Roadster custom tuned, and holy cripes it felt like a rocketship afterwards!! Here's the only issue...for the past couple days, the car feels like it's back to stock programming. I checked hoses, oil, etc and after finding no physical signs of the problem, figured I'd call the folks that did my tuning. When I explained the situation and asked if it were possible for the ECU to "reset" itself back to stock, I was told that this was not at all possible. Is that the truth or is someone blowing smoke up my exit only area??

I am totally stumped, live and work pretty far from the tuning shop, and have no engine codes being set off....Any ideas??? Any input is much appreciated!