Common problem. The small white plastic clip that connects the latch to the cable on the back of the lock comes adrift. You can sometimes get it back in bu hitting the lock or putting a long thin screwdriver thru the grille and onto the white plastic block on the end of the cable and giving it a smack. 50/50 if this works but its an easy enough thing to try. I do loads of these at work and im pretty good at sorting them without having to replace or remove anything. Shame your not closer or id be happy to help out.