Xiaomi India — automatically switched off and removed data

Address:

New Delhi, Delhi, 110052

Sir/mam,
I want your concerned attention towards the problem which i am facing alot. I buy this device on march 1st, 2018 and the device is get authontically switched off and erase all the data. Sometimes when i was doing my work on phone is automatic getting switched off an even if it is on charger plugin this device repeats the same process (Switched off and erased all the data)
Kindly provide your concerned suggesstions towards the problem either replace this device with the new one or return my payment.
Thanking you