Oh, those fallen girls. Talk to the reverend at the church, often they have a program to help fallen girls!
Seriously, I'm not sure in your case. Did it just come of as the entire piece or did it break somwhere? I helped someone and used just a tiny drop of cyanoacrylate adhesive (superglue). At least it was working for a few minutes when we tested it. I don't know if it vibrated lose.
Frankly I was worried using that glue. It would be easy to glue the mechanism fast.