Airtel — call for disconnection of mobile number

I have received a call by deepak (No: [protected]) claiming to be one of airtel's official. He asked for my aadhar number and rudely told me to do so within half hour otherwise my number will be blocked. I already have registered my aadhar number for more than a year and am linked with airtel for almost 17 years. Now i can't reach his number. Nobody from the customer care are picking up my call.