Refund of your RV due to wall paper peeling? Not very likely.
Seems like a pretty minor issue, though I am certain in your mind
it is a pretty big deal, especially since it seems you have been jacked
around for quite a while.
First off, shame on the dealership for treating you that way.
Second, what has been Winnebago's response been? Can you get authorization to take it somewhere else? Maybe as a last resort, have a professional wall paper guy replace the wallpaper, the you could sue for recovery. Seems like you have done all you can dealership wise.
I hate to see people having to take legal action to get things done, but in most cases, once a company has been served with a summons, things generally get done.
FWIW, add a few paragraphs, makes for easier reading.
My advice is worth exactly what you paid for it.