I don't know about your particular extended warranty. I do have some experience though.

I had a printer that took 18 months to get back from warranty with all sorts of excuses like your folks are experiencing now. At the end of the saga we got a new printer that had much lower specs than the one that broke. I also have a friend that has been waiting for six months for the warranty company to fix his broken plasma.

To me it sounds like they are just trying to get rid of you with a quick excuse. The only thing you can do is constantly hassle them to fix it and stick to your guns. Eventually they will cave and give you what you paid for.