Awaiting payments

I have made a payment last month around 27/09/2020 however I have been deducted for the amount. I have sent required documentation however I have still not been refunded till date. On 21/10/2020 I made a payment of R299.00 on the MTN contract website however initial payment stated failed so I tried again and then my payment had went through twice. I waited for a few days hoping payment would be reversed however it still has not. I contacted MTN and was told to send required documents such as a bank statement. I have sent a transaction list from my bank of successful payments and I get a response stating I cannot send a bank statement and that the reference that I used to pay needs to be provided. I did not use any reference on the website just logged in to my account and chose pay now. Why am I being inconvenienced. Is there anything else required. I pay before my due date as our salary date is not fixed and I don't want my debits to bounce and be charged extra. Now my credit card is in a negative balance because I am awaiting for funds to be reversed from MTN