I had the same problem and I agree with Mike that the best way is to change the whole thing, but sometimes it too complicated for some people. I just didn’t have enough space and it was raining for some time. I used reinforcement plates, but first you have to try to bend it back to it will be flat with remaining piece of metal. I used pliers, spanners and screwdrivers. It's hard but possible.
First, I used one plate and tightened it from outside (be careful not to damage the thread in check strap when bending back) and when the whole thing got more flat I placed second plate inside and tightened it.
This is very good advice and OOF is the first place, where I found information about reinforcement plates (I had to give Part No when ordering in Vx as they didnt sell any in few years) I just have two comments on this advice:
1. You don’t have to cut the plate to fit it. Take the electrical connector (is near to the strap) out (twist off and pull it - use big pliers and take red plug out) and as you will put the plate in the hole there, it will come in the hole in check strap area.
2. It's not worth to paint the plate as I tried several ones and it always comes off.