Not to be argumentative, but I would not try to bend that arm. They are brittle hard parts. I've replaced two of them and you can see just how brittle they are at the break.
Something is out of adjustment under that face plate. It's better to figure out where to adjust, than to try brute force.
Also if the arm is already bent, trying to straighten it may well break it. That's been discussed here to more than once.
Joe