CANCEL MY CONTRACT, I’M PAYING FOR SOMETHING I DONT KNOW

A made a contract and finished paying it off 2-3 years ago, they’ve been deducting money from me even after cancellation, they are busy saying they sent a sim that they send the monthly airtime to, I have never received that SIM card, I’m tired of paying for something that I don’t see or use, I’m also tired of visiting their branches for contract cancellation and sending emails with no feedback, this is exploitation!