The after-sale service problems have got to be dependent on location or inconsistent policies/managerial responses.
I'd also was having battery, overheating, keyboard instability and the infamous "insomnia" after the Bad Firmware update. After the expected Firmware Fix did not materialize yesterday, out of sheer frustration, got MS support on the phone, and lo and behold, they were willing, even eager, to make a deal. A refund or exchange, and I took the latter, organized through the local retail store (where I bought it in the first place).
Back in December they weren't so helpful, so something seems to have changed. The failure to produce the firmware fix maybe unleashed a torrent of dissatisfaction, certainly a lot of grousing and discouragement.
Hopefully, you will get a better response now. I'd certainly emphasize the above factors as they apply to your situation. I'll keep a good thought it will shake something loose, and you'll get your problem resolved.
I'm going to call store I purchased from and see if I can get a refund. I want to love the device but I don't have the time to deal with it. It has knocked me on my a$$ in being behind in my design work at this point.