Ouch!! I had a similar experience with a dealer in Tucson. They tried moving with a forklift without putting the pins in the sidewinder and bent the corner like yours and also the actual king pin floating plate (airborne version with the air bag, like yours). They replaced the whole hitch, turret, and they had an excellent welder on staff that cut off the welded hitch attachment plates and replaced them. That was 5 years ago and we have had no problems.
Now if I ever leave it for work to be done, I put in the pins and attach red flags so I remember to remove them when I pick it up
I would call my insurance, send them the pics, and get them involved if you don't feel the dealership is addressing this completely. The adjuster should be able to see if any other damage was done that might need to be addressed. When this type of accident occurs, they can also drop the rig on the front jacks when they realize what is happening, so check those out also. They replaced a footpad on one of our front levelup jacks.
Your insurance will work with their insurance and you shouldn't have a problem with your rates going up as your insurance will not have paid.
Good luck and let us know how it turns out!!
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Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD Duramax
Reese Fifth Airborne Sidewinder