If it were me, I'd get rid of the extension first, then I'd get the weight distribution system and use that. If you don't have the air suspension, that setup should work fine. However, from the pictures, it's hard to see what parts are bent. I'd definitely try to take it apart and see what's up. I don't know why the plastic is sagging. It's just trim. The receiver mount is bolted to the frame and not to the bumper. It could be that one bolt broke or has come loose and is pulling it down. I'll have to look under mine. I tow all the time, but haven't ever towed that much weight very often or very far.
If you really need help with this, I've found that taking your rig by an RV place with a good service department will help you troubleshoot any problems you may be having with your tow rig. Not cheap, but it's money well spent if you want it done right and you don't have a shop or tools to do it yourself.
