Airtel — Deactivated account assigned to someone with my identity

Hi, 7 years back I was using one airtel number that was deactivated on itself. But I changed my number and left it some time after that number got activated that time i didn't had much awareness I left it. After seven years same number is assigned to someone I guess, They were trying to login in Paytm which was connected to my mail ID. I don't remember that number now. I only know last 3 digits. So I need to have a confirmation whether the number is still with my name on it. if so I want to change it.