Lenovo — complaining about smartphone lenovo vibe x3

Address:

New Delhi, Delhi, 110022

I purchased lenovo vibe x3 phone back in september 2016 and from that date i have already visited service center thrice with three diffrent issues,
The current issue i am facing is with the networks in the phone. Please look into it asap. I am completely frustrated with the phone's performance. And i request lenovo to change my handset with a new one at the earliest.
The service center staff is not very helpful and they always try to deny the isuue i face with the handset.