MTN - billing what they want, when they want.

I have been paying MTN cash for my contract for the past 3 years. Now I wanted to cancel my contract because it is at the end and they make the process so impossible. I then decided its fine let me just upgrade to a data package for 250 a month 25 gig. Great stuff hey, but they would not do this without my banking details. I agreed and within the fist month they messed up the debit orders. I paid them on the 31 of May my usual 1000 which was supposed to be the last time. They then debited me 612.44 the 02 June and a further 389.45. I phoned the contact centre who said it was not supposed to happen. Not being able to tell me why it happened. Now they want a statement after the case has been opened. I bank with FNB, they only provide statements on the 19th. I was waiting for my banker to reply and then they closed the case, I did respond with screenshots with references from my app. All the evidence they would need but no, its just easier to close the case. I then got an sms today that I need to pay the 1000 again for Feb 2024? What the hell is going on with these systems. I am disgusted by this service. I have opened a case again. BO*** fix this MTN. I have been a customer for over 10 years. Not happy.