I'm gonna guess something got knocked in a way that's preventing it from turning right, but beyond that, I'm not as familiar with the older modern Vespas. If it were me, my next step would be to curse at it in Klingon, plus a few other languages.

I know there are others around here that are far more savvy when it comes to locks. Bumping the thread a bit here for ya...
I will say, just for your future reference, that the older model LT (yours) had a whole lot in common with the Vespa ET series. If you happen to search for things around here on MV and don't find what you need specific to the LT, try whatever applies to the ET.