Xiaomi India — mi 32inch 4a led tv repairing problem

My mi 32 inch 4a led tv is stopped so i complaint in mi costomer care.
So one day service engineer's helper visit and check tv but not physically only check normally and contact with his service engineer and say problem in mother board.
And he says repairing charge is 4200 and gone.
So the next day i on tv and it will be start normally without any repair but after 2 day o[censored]se tv is automatically off and not working.
So i complaint in costumer care but they not properly reply and not repair tv and charge is too high