I think you are on the right track with regards to the support screws being sheered off. I do think it is strange that JOSAM isn't helping more. Maybe they feel they might make it worse and be liable?
Try your local Craigslist RV section for FSBO RVs. You might be able to take into a dealer also if you need to do an In-and-Out for financing purposes.
In my experience a 3rd party/specialized RV financing company is great for getting a quote you can take to your bank or credit union as leverage to get a better rate or better terms.