Airtel — my mobile number is allocated to someone else

Address:

560077

I contacted airtel customer service (Date 12 march 2018) and created service request for mobile number is not working and it has been assigned to another person and was told that nothing could be done about my problem.
I believe that this response is unfair because they take 1 week to resolve this issue. I got same issue (Assigned my mobile number to another person) again on march 26, 2018
I called nodal team and sent email to customer care requesting for reopen service request or to create new ticket. But they did not do anything one entire day.
Finally, they created new service request by 27 march. They closed this service request without informing me and created one more service request by 28 march. I came to know my number is allocated to some one else. This number is update in all my bank accounts, pan detail, aadhaar account, bank acounts, and credit cards, and other utility bills.
Now the other person who got my mobile number is getting all my bank information and all other confidential details.