Removal of front seat belts - side trim ?

[Ivan141]

If it is what I think it is, it's a very small piece of plastic where the belt comes though the panel. You can slot it to remove the belt, do it in a place where it wont damage the belt when you put it back and there should be no problem.
Otherwise epoxy is a bitch to work with, I find a soldering iron works best for joining pieces of plastic.. just weld the sucker back together, maybe add some extra plastic from the back to strengthen it, the outside can be filled and painted, or left alone.