Lenovo — Very frequently switching off Mobile

Address:

Aurangabad, Bihar, 824101

I have bought a lenovo Zuk z1 from Amazon.in May'16 but it is creating problem for me getting off very frequently. Kindly extend your support. This product I have bought with very zeal but the way it is getting off, it has disppointed me a lot and sometimes I have missed some very important call which resulted in a frustration for me. I hope you people at Lenovo must do definitely for me to get out from this sort of trouble.