Can he do this?

Well, to be fair to him, he was despatched to your house to help you and noone called to cancel the job, so I would suggest that out of goodwill, you give him a little something. You don't have to give him $100 cuz he did nothing with the lock, but to have to drive all the way there to be told to go home is also not nice. And since he knows where you live, it's best that this ends amicably for all parties. You would like to sleep well too, I'm sure.