MTN South Africa, Empty promises and ********** transactions

Dear MTN

I am trying to cancel my Fixed LTE month-to-month with no success. I am being directed from one department to another, 135, *** and ***, with no success. I got a confirmation sms stating cancellation is due on 17 August, yet I received an invoice for September. Please note that should the debit order go off, after I cancelled, I will report the agent helping me for *****, as I gave a months notice and she confirmed that there are no penalties due.