Airtel — cross connection and call failure

Address:

244001

For the last 2 days, I havent been able to call anybody without the cross connection problem. I call someone and someone else picks up. Also the number I have called gets a call from my number later but with someone else speaking.
I tried calling 121 for this, but it says that my number is invalid and wont let me connect.
It feels like my number has somehow been given to someone else. It is very troubling as I cannot even call Airtel customer care as it wont let me.