Best thing to do, go to a different garage and explain what has apparently been done, how it previously felt and after they fiddled with it and get a fresh set of eyes on it, maybe the garage you went to have done something completely wrong or broken something and don’t want to admit it (VW trannys aren’t cheap to replace if they have) and see what they say.
If your short shifter isn’t factory standard I would remove it and get it set back up normal again and working properly so you can drive the car and see if everything works okay or if there’s any problems that pop up that can then only be down to the standard parts. can always install that short shifter again if there’s no issues but may make it easier to set up and avoid any costly problems.
If you’ve had continuous problems with the same garage and you don’t think they’ve done it right then get the work done by another garage.