I have had similar experiences dealing with their CS.

That said however, you NEED to take a deep breath. Then, calmly collection your information on a single sheet of paper. Only the vital info, with underneath all your receipts and timeline regarding specific phone calls/store visits/purchase dates/warranty paperwork/etc. IME Costco is more than capable of handling the issue if you are persistent yet firm/polite. My dad had a replacement HDTV in one week via this route. If the overseas concierge won't assist adequately, call their corporate office and detail how you were treated. Again, it's *how* you remain persistent that matters. They will help(!)

Good luck and let us know how it goes.

p.s. another place to get additional info is AVS forums.