Understand. Thanks for responding.
By the way, what is your country? I might be able to wrangle up some additional Level 4 help for other avenues of appeal if we knew where you are.
An Apple Store or AASP is supposed to have a tester to plug into the computer that will identify whether the 8600M GT has failed. Did you see them do such a test? Some have said their computer "passed" the test (that is, a "no failure" reading) when they first arrived at the store or service provider but, once they let it warm up in the store, the gadget detected the failure. Makes some sense, as the failures are primarily heat-related.
So, if the tester gadget didn't sound the alarm, it could mean something else is afoot, or the 8600M GT wasn't hot enough to choke.
I don't have an e-mail for the people to which you should address a protest; all that I have is a toll-free number for N. America. However, the department is called Customer Relations. They are the upper tier of support and, often, a calmly presented, well-documented review of issues/problems you have with the computer can lead to a satisfactory resolution. Calm is the key here. They probably get dozens of rant letters to every calm, considered one so, in this case, a peaceful yet knowing demeanor is a good thing. You'd have to write them, as far as I know, unless we find another option when we learn your location. Use the main Apple address:
Apple
ATTN: Customer Relations
1 Infinite Loop
Cupertino, CA 95014
Again, with an idea of where you are, I might be able to find some extra help for you within these forums.