[Evgeni]

Mate, I just had the same problem yesterday where the key was not opening the door. I took the trim off the door to find that one of the links that joins the latch to the key barrel was just hanging on to its plastic retainer.
Lucky it was still on, otherwise I probably would have needed to smash the window to get in. Anyway, fixed for now, but will probably go and get a replacement from the wreckers or find some other way to secure it.