Airtel — unable to receive incoming calls

Address: Hyderabad, Andhra Pradesh

Website: airtel.in

Whenever somebody is trying to call me ([protected]) they hear a voice saying"this is an invalid number", for the record i am bale to make outgoing calls and also use the internet services without any issues.

But unable to receive incoming calls.
The problem persists from (17th dec 2017, 08:30 a. M) i have tried to reach the customer care but no one is able to rectify my problem