Xiaomi India — redmi 3s prime automatically bricked

Address:	Kolkata, West Bengal, 700150
Website:	mi.com/in

On 18th of october 2016 i bought redmi 3s prime and then after using 6 months i had an issue with charging. Charging get disconnected and connected automatically and on may they fixed it. Then it happen on august also. After that they took 4 days and also fixed it. On this repairing they changed the motherboard.
After using several months.
On 25th of october at 8pm when i was watching youtube. The phone restarts it self and stuck at mi logo. I took the device to service. After diagnose they asked for 6312/- for changing the mother-board once again as it was not in warranty.
I haven't done a single modification to this device though this it is now not working and stuck at mi logo. There is also no physical or liquid damage.

I need it to repaired or replaced.

Invoice:- https://goo.gl/iQau98