Motherboard of Mi4i got damaged and I am not getting replacement now, suggest what should be the procedure to deal with this?

I bought a Mi4i cellphone from FLIPKART on 7th May 2015.
I bought the phone to gift my brother who visited me approx 25days after I purchased the cellphone. I checked the basic functionality of the phone when it was delivered to me, then the charger was working fine.
But afterwards my brother came up complaining that the phone is not charging(when the battery completely drained out). I visited the nearest service centre and they said that some "Hardware is missing" from the device.

I had visited the service center and called multipe times to MI call center for my issue. But they failed to provide me proper solution. Customer Service team also guaranteed me to drop a mail explaining the issues I am facing. I am frustated with the service provided and feeling cheated.

Flipkart official are out of this saying they have 1 month replacement policy which has lapsed. I have heard of GREY MARKETING in flipkart and now I am sure of it.