Xiaomi India — redmi 7 display problem and. power button

Address:

462023

1) i have visited service centre for around 4 times but got no results
2) its power button does not work sometime mobile doesnt start
3) sensor is not working when someone call comes the screen become black we have to wait for another person to cut the call line
4) sometime screen become black mobile doesnt start
Model;: redmi 7