Yea, I am thinking you are not getting good mechanical contact with the bent over clip. Others have found replacement clips, but you also are going to need to fix the bent slot.
I would not try to bend the frame itself, you will likely make it worse. If you can fashion a small tool out of a piece of metal with a "back hook" in it, or perhaps buy a small hook-and-pick tool set like this one:
I would try and buy a set like this at your local hardware store rather than on-line, as you want to make sure they are small enough to do the job - and you can't tell that from a photo. Even a screwdriver with a bent tip would probably work - anything you can use to get the tip under the bent slot.
Anyway, if you can obtain such a set, perhaps you can put one of the hooks into the slot and pull out to straighten it; or maybe tap the front lightly with a small hammer while holding the backside with one of the hooks.
You know, even one of those small bent nose needle nose pliers might even work. I've had one for years in my tool box, and it has had no realistic purpose. Perhaps one of those might work - if you can find one small enough.
What would really probably work is if you could cut a slot into a small piece of metal, with the slot thickness just larger than the metal thickness. Perhaps you could take a Phillips screwdriver, cut the end off, then cut a slot half-way through it. Like this:
You could then insert the slot of your "tool" into the square hole working around the perimeter, bend it straight again. Kind of like a micro pry-bar.
But by the time you fix the slot (which is not 100% assured) and buy new clips, it might not be any more expensive to buy a new screen.
However, this seems to be a chronic problem with these things, so the tool might be a good investment for future repairs.