Airtel — coverage & data speed issue

Address:

Kolkata, West Bengal, 700028

I am using airtel from last 4 month, but getting fluctuation in coverage in my house & also not getting speed of internet also. 4g is getting very less time that also not stable. Complain several time from last 4 month. But still problem not resolved. I am staying at kolkata city, but still here facing coverage issue from long time. Otherwise i need to change my operator.