I had typically warped rear vert panels, as the pictures show. Plus a crack. I heated the plastic up with a heat gun until it was very floppy but not melting. Then I clamped it to some pieces of wood and let it cool down.
It worked great on the gap by the door latch. I was going to add a third screw there, but not now. I also was able to bend the tip back into place quite nicely. We'll see what happens when it gets about 80 degrees though!
Done:
