I'm really sorry that you've gotten into this mess and it does indeed sound like you were "taken", unless you got is at a really dirt cheap price that will allow you to spend the money for the necessary repairs.
I would strongly suggest that you try to find a local independent RV tech with a good reputation that can check it out and advise you on the proper course of action. I think you've bit off more than you can chew without some help.
Good luck, happy trails, and God bless!
Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD