Airtel — airtel - all lines busy

From 30-40 days i am hardly able to make any calls. Every time i try calling, i am hearing a lady saying all lines are busy in all languages. I try calling at least 7-8 times and if i am lucky then my call will get connected. On a daily basis, i am spending at least 30 mins trying connecting itself.
From 4 days i stopped using normal calls and was only using whatsapp calls. Thanks to whatsapp,

My connection is from mumbai area. This is happening in all the areas, i tried in other states also but the same situation.

This is so frustrating! This is very bad customer experience by airtel

I have been using airtel for 7 years now. Now i am planning to port because i am seriously disappointed by them.