MTN NOT HELPFUL AT ALL

I am very disappointed with MTN's service. After months of excellent service without hassles, then they do this. MTN sent me a message on the 1st of October that I should pay for my contract phone or else they would switch it off. I did not understand this because they usually just debit the amount owed every month. I then paid the amount due and they sent me a confirmation that they have received the payment. Next thing, boom!! MTN has debited twice the amount that they usually debit after I have already paid them. I really do not understand this. When I called the consultant, they said that they can't see the debit on their side and there was no debit scheduled. And their solution was that I go to the store and show them my bank statement, so now I have to waste my time to go to a freaking MTN store as if I'm the one in the wrong, they did not even try to help. I would like MTN to please assist me with this because they basically stole from me and then I still have to incur the banking fees.