OnePlus India — issues in phone which is under warranty

Address:

Ahmedabad, Gujarat, 380015

Dear sir
I am using one plus 3t i am facing lot of issues. I have made several complaint on their email, twitter, customer care, tele-executies, etc. I m now frustrated. My mental peace is lost. I want to sue one plus india as they have cheated me by providing worst quality of phone at higher cost. I want replacement or money back.
Problem faced are
1) video playing errors
2) phone hanging issue
3) phone gets sleep and switch off after drawing pattern post reboot.

Below is twitter link where complaints were made.https://twitter.com/TheAkashBorse/status/[protected]?s=19