Airtel — Airtel rep harassing and threatening calls about number giving up

I recently got my airtel post paid connection with a number ending with 9999. System has not charged me anything on this number and I took it and linked with all banks an Government agencies. A week after I got this number I started getting calls from the local airtel office asking me to give up my number otherwise I would be at risk.

I linked this number to all my financial and government transactions. I cannot giveup this number now. I complained to Airtel customer service and they said the issue is resolved and I should not get any more calls. Within an hour after that I got calls again from same Airtel A.S.Rao Nagar branch and threatening me that police would come to my home, I will be at risk etc. This is a clear harassment and threatening done by the Airtel rep to get this number. This is not what I expected out of Airtel.

Airtel rep says he is going to disconnect my number which I did not ask for.

Can you please let me know the options I have to resolve this issue?