Airtel — internet and calling

Address:

Meerut, Uttar Pradesh, 250004

I am not able to make or take calls via mh airtel sim as whenever i call someone after few rings the network goes off or slighty depletes to zero and the call gets ended. Same happens when i take calls.
I am facing this issue since a month or two now. And now i am facing internet issues too. I used to get nearly 2.5-3 mbps downloading speed which has gone down to 300-400 kbps along with this calling issue. I am not even able to make calls and use my internet properly which i paid for. Airtel's services are worsening day by day.