Cancelation Department not doing their job.

My contract with MTN finished in May 2025 then on 9 June 2025 at 14H30 I called the cancellation department and spoke to Luyolo Qedile told him I want to cancel my contract to go to pre-paid. He assisted me under ref nr ***. I asked him when will the last debit order be going off and I was informed the line will go to pre-paid on 07/07/2025 and the last debit order will go off 01/07/2025. Check the calls as all calls are recorded. I then called again 13/07/2025 to check because the line was still active and I was informed that Luyolo did not close my contract and now I will be billed again on 01/08/2025. I will not pay that debit order as I did do everything correctly from my side, I called and canceled and gave my 30days notice. Now because of people at MTN that did not do their jobs correctly they want to penalize me and hold me responsible for another payment. I will not pay the installment they can get the money from Luyolo Qedile.