Kryptonite new york fahgettaboudit u-lock disaster

Also when you go back to it try a spray lube into the lock, I am not sure about the lock on this particular model, but I have had a barrel where some internal part has failed to lock into place. Lubing it, and giving it a bit of a whack got it to engage again and the key was able to operate the tumblers.
Fingers crossed you get this sorted.

i may have totally made this up - but i swear i read on here that you should use olive oil instead of wd40 etc...can't remember why, but im sure i read that.