Huawei — facing problem of getting switch off while using in honor 9i

Address:

Bathinda, Punjab, 151001

M using honor 9i phone... And it get switch off automatically nd then get restart again automatically while m using.. It makes me annoyed and some time my important task will nt get completed... Even sometimes it get switched off nd restart while m on call. So please tell me the process to solve this problem. I bought this phone in dec 2017 it's been only 6mnths nd m facing this problem past 4 months. I guess this is not acceptable from a new device.