When I use key to lock door windows goes down automatically unable to lock car

They use plastic clips to secure the rods that lock and unlock doors. Sounds like the clips are broken or the rods(metal) need adjusted/ bent..

Look for a vacuum leak under the rubber bellows at the door hinge area. This generation VW had vacuum actuated loor locks and the connections could come apart, typically in the hinge areas where flex occurs.

One of your door switches is faulty. You will need to have it scanned to see which door it is then replace the door latch assy. in that door.

Replace the battery in your key ring.

first thing i would do is remove batteries from your key fobs.one could be "acting out' intermittently and enabaling auto down feature.another possibility is left front door lock cylinder switch doing this.do all doors unlock when you cycle door key switch twice?if not definitely something to look at esp if someone recently tried to slim jim your door.

If the trunk works try it. If not any place that sales auto alarms can fix it. An a tow guy should have a slim jim

try reseting alarm system.
with key in drivers door, unlock/ hold key over for 30 secs then lock/hold key over for 30 secs then press unlock button on remote
the system is now reset.if windows go up/down you have comfort settings on your computer.nice.....
if rear door still locked you will need to strip it down to find fault.then reset again...

disconnect battery reconect after 5 mins on reconnection rear window will go down , use key in rear lock to reset rear window, door lock should now work, if not try rear door relays behind left hand rear panel.

this is classed as security and the software is encrypted evan on a 9yr old car ,so its dealer only or disconnect the power suppy for the central door locking.Do what i do and leave the dammed thing open ,you dont get your windows broken