MTN Home Internet not canceled

This is going to be a long one.

So late year, in November I think, I got the month-to-month home internet wifi router from MTN. I was paying about R265 at the time until February 2025 when they increased the fee to R295. At the end August 2025, I canceled the thing. I called them beforehand to ask what the process was and I was told by the consultant (his name was Lebohang) that I only needed to return the router to any MTN store and that's it. Cool. So 29th August, I returned it and while signing the termination agreement I noticed that they say you need to give 20 day notice, which was news to me and I told the consultant exactly that. She said that they will be taking the D/O on the 4th of September as normal since it falls between the 20 days, which was not great because I wouldn't even be using the damn thing. She said that they would return the money into my account. I didn't have that money so when the day came the D/O rejected. Since they were going to return the money anyway it didn't seem necessary for me to stress about it, so I didn't. On the 4th of October again a D/O came through but it rejected because again, I don't have the money. And I called them and explained everything I've typed above. The consultant said that the cancelation was done and she will escalate the matter and get back to me. She never got back to me. Towards the end of October I received a notification of a failed D/O from MTN, for an amount of R2500. I do not understand why they tried to take R2500 from me, and I called to get answers. I was put on hold until eventually my airtime ran out. Then they called me back saying that 'they' will look into it and get back to me. Oh my days, I had to call them back again and the same lady, Lorraine, said they still do not have any feedback yet. I wait a couple of days. But then I got a call from some guy also from MTN who tried to sell me a contract they had a promotion on. But I had no interest due to obvious reasons. I asked him if this query has been resolved and asked him why they are taking R2500. Not this guy telling me that my previous D/O's 'probably' did not go through and I owe them. But that did not make sense because if that was the case, I would have been informed of that, right? The wifi wouldn't work, right? I told him as much, that at least the money would have returned to my account and I would know. but that was obviously not the case. I went to my banking app to check my bank statements, and while doijgbthat he said he has 'other customers to deal with' and the call ended. I went through my statements and of course there is nothing that says the debit orders did not go through. I called yet again and asked them if they receive all my payments, and Lorraine said they did. And if there was ever an issue I would be informed of that. So I explained my interaction with that sales guy and Lorraine said that I should ignore that guy because he's just a sales consultant trying to make Sales. That's pretty ****ty, in so ***********, both these people I spoke to. I followed up again on the ridiculous amount they tried taking, and she said that when they returned the router to their warehouse, the people there could not see some document and that's what happened. She went on to day that things should be fine now because they have to documents. The explanation made no sense, nothing here makes any sense and I feel like they are just ripping me off at this point because if the cancelation only take 20 days they why the hell am I here? This was yesterday. Today I got an invoice stating how much I owe, apparently, and now for the reason why I came to Hello Peter is because my fellow internet users, I had a failed D/O for R2854. I'm going to lose my mind. I am not getting anywhere with this and I just need help. I can't stop the D/O from my banks side, MTN has to do that but apparently that too hard for them.

that's my story folks, how do I end this nightmare?