From what you're describing , it sounds like the paddle which slots into the lock mechanism has broken which is quite common.
The paddles tend to break where they hooked through the barrel .
If you undo the torx screw and remove the door handle you'll be able to confirm this.
If your ' lucky' you may find that the broken paddle is still slotted into the lock mechanism which you should be able to pull out,although you may find that the broken pieces have dropped to the bottom of the door (which normally means taking the door card off to retrieve them otherwise they may rattle about )
VW supply replacements which have a thicker/strengthend hook
The parts you will require from VW are a) modified paddle
                            b) modified barrel
                            c) modified eccentric
                            d) two springs
The parts cost just over £30 from VW (remember to order two of each if your doing both doors)
You then need to 1) Remove broken parts and barrel
             2) Remove the tumblers and small springs from the old barrel making sure you replace one at a time to ensure they go back in their relevent places  (then push the key into the new barrel to make sure the tumblers are flush with the barrel when the key is inserted )
             3) Lubricate the new barrel and tumblers and reassemble in reverse order
Hope this helpsÂÂÂ
