Lenovo Z2 Plus — lenovo z2 plus having switched off over and over

Address:

Mysore, Karnataka, 570022

I bought a new lenovo z2 plus phone on may 2017, and it's specs are good and great but doesn't make a great phone having bugs in it, everything else is great in this phone except for switching off, suddenly the phone screen starts blinking and turns off, now it's august still the problem exist, and when taken to lenovo centre they said this phone has problems we can't do anything, and now my dad won't buy me another phone, please send a new update fixing the bugs for this phone it's a humble request, please do it soon as possible