Impossible to terminate MTN contract.

I terminated my contract with MTN on 17/06/2021. I paid a penalty since this was done before end of term for that contract. The service was deactivated on that date, but without notice MTN began debiting my bank account on 01/04/2022. I have visited my local MTN branches and tried stop this and been told several times that the contract is terminated, but the debits continue. Worryingly, the address and cell number they have on my account are NOT MINE. They have my name, ID and bank account number. The matter is currently being investigated.