MTN just wont stop with debit orders on closed contract.

i had a contract with MTN and when my contract ended in Dec 2019. i called to not renew my contract but till this day every month i still have to dispute my debit order because they keep deducting money from me . MTN just has a way of making customers unhappy when it comes to debit orders deducting money thats not suppose to be taken then when its time for refunds they take month to refund but quick to take money from customers. Im not going to call in again to ask for this to end i will let it pile up and ask my lawyer to handle this i have proof of ref numbers from my calls that i ask them to stop this .