Worst experience

I was referred by a friend who had nothing but to say about mtn, so I went and took out a contract which was a bundle deal for an s8 and j5 pro - took the contract on the 12 th of October and I was advised it doesn't debit the same month double checked with the sales advisor Yashoda from gateway shop who assured me the first debit will only come out on the 30 th of November, to my surprise on the 31 st of October I see a debit of R688.00 from mtn then I called 808 and spoke to an advisor who gave me attitude and told no thats not possible without checking my account but when he heard that I'm not happy he then asked for my details to check my account then he says oh yes u were debitted but this shouldn't be the case, told me they loggin a ticket and I should wait 48 hours with no response I go to the store and they also told me I was billed in error and told me they logging another ticket and response should take 48 hours, this debit had inconvienced me as I had other accounts unpaid so I decided to go to the bank and reverse the debit, then suddenly I owe them R1444.46. End of November I paid R744.00 which I knew I had to then a few days later my lines have been closed witout any communication from mtn how is this treating a customer fairly? Being in the wrong and still cause me more inconvenience?