Golf Mk4 rear door won't unlock

[JadeL]

I have a Mk4 golf, my rear passenger door won't unlock and I can't open it from the inside or outside... How can I unlock the door to be able to open it please????
I have to unlock my car, from the passenger side using my key in the door.
It was working till Saturday worked fine earlier in the day and stopped working I had to get my child out through the other back door. I don't think the child lock is on as pretty sure I've opened it from the inside before. But may be wrong. Also when pulling inside handle the lock button that pops up when unlocked dosent move when pulling inside handle.
I don't have the money to pay to get it fixed right now.

[SR123]

I created this video a while back to explain another possible solution to this - it involves flicking the little plastic lever as mentioned above: How to open a VW rear door that is locked and won't open at all - YouTube