Welcome to the club and sorry to hear of the problem with the doors, have you or do you know someone with vcds/vagcom to see if it gives any indication as to why the doors won't unlock, it might point you in the right direction
When you press the keyfob to unlock the doors can you hear the mechanisms trying to work on the passenger doors, I had a broken wire on the front passenger door that would work randomly, while fixing the wire I shorted it and it stopped the rear door working properly, not sure why to be honest, but when I got the front wiring sorted out, the front door worked fine, ended up having to get a locking mechanism for the back, not saying it's the same, but the wiring in the doors seems to be a common problem,