Cancelling contract complaint

I took a contract phone in 2018 around June it was a two year contract . Paid off the contract in 2019 then 2020 I cancelled it and paid the penalties before canceling. It seems vodacom decided not to close the account even though my number is now prepaid . A year later I am receiving call from vodacom claiming that I owe money and they took my case to their legal team. I would really appreciate it if they can resolve this matter making people’s credit records look bad over their own mistake is unacceptable.