Terrible service from MTN and over charged for their error

I was charged R1710 by MTN when my contract amount usually is approximately R370. I called to cancel in due time but due to MTN billing having an issue my debit did not go through and a case was opened. Mtn reference Case number:BO*** Reference: ***. I was told that it will be sorted and it was not. I called multiple times to cancel and was not assisted successfully. I was told that I will not be charged late fees and a higher out of contract rate as the issue was a billing issue on MTNs side. I was not told that their was an option to pay online or in-store. I was also not giving the option of them redoing the debit orders immediately. I was told that an investigation needed to be done. MTN then realized that it was an error that affected many customers but did not rectify it or call me back as promised.

I should not be penalized with November billing at a higher rate due to MTN negligence. I should be refunded the amount that was ****** from me by MTN. I have called and emailed multiple times and have not gotten any resolution.