One heck of a story.
I can't say anything regarding to your misfortune besides you really have a bad luck.
So far everything is fine with my Asus and hopefully still stays.
The part on the incompetence of the staff at fixing centre I agree. They're worse than a bunch of monkeys. I don't know how the even got the job to begin with. I asked a lot of questions to Asus directly via support from USA ones to the European ones and not one could give me a reply! To my luck I myself am smart enough so I could figure out the answers myself. It is sad that a company such as asus cannot have more proper support. But I guess you cannot have everything in life. The laptops are great build, cheap but unfortunately the support is the worst.
If you didn't give up on gaming laptops completely I advise you to go for Alienware, MSI or Clevo. They have better support than asus and better build quality (You don't have to put your whole laptop apart just to change the paste for example) but they are more expensive and even that is only in some countries.
Asus Rog G750JZ
Screen: 1920x1080 17.3'
CPU: Intel® Core™ i7-4700HQ (3.4Ghz @ -70mV)
GPU: GeForce GTX 880M 4GB (OC +125Mhz Core, +600Mhz Memory @ 1.062V)
RAM: Samsung 32GB 1600MHz
Storage #1: Samsung Evo 840 250GB
Storage #2: Samsung Evo 850 500GB
Storage #3: Seagate Barracuda 2TB
Storage #4: Samsung Evo 128GB MicroSD