I don't have any experience with that machine so I can't offer suggestions on it's repair. I'll leave that to the 'experts'.
Do you have a quilting friend that could come over and help you and hubby go over EVERYTHING in the set up...everything. Maybe some simple small thing is preventing it from working properly and both of you may be just overlooking it. A fresh, new pair of eyes would help...even if the quilting friend doesn't know anything about the machine. Hey it doesn't even need to be a quilting friend. Sometimes people who know nothing about something will ask 'just the right' question :).
As far as the dealer ... why are you going to his store to have him fix the machine at your home? Shouldn't he be coming to you? I'd remain civil and start talking Better Business Bureau to both the dealer and the Corporate Headquarters. Start documenting EVERY conversation. Date, Time, and who said what. Ask a person to spell their last name because you're taking notes, they'll know you mean business! There are a number of phone number look up locations on the web that allow you to post comments on services received from companies. I'd mention that to the dealer too and use it if necessary to get this issued resolved.