Apple India — Complain about macbook

Address:

Nainital, Uttarakhand, 263139

I purchased a mac book air in nov 2014 and since then there is a problem in it.
It gets shut down on its own any time and do not get start.
After trying for a day or two suddenly it starts up. i have contacted the customer care and store many many times.
What to do. service center ppl also dont no - they have replaced the battery, motherboard screen twice.
Its still in warranty.

Please help.