MTN South Africa Poor service and ****

Received very bad service service from MTN as they cannot resolve any issues they created them selves. Firstly my contract term has come to an end with them and now all of a sudden I have missed a payment for September. Constantly provided details that the debit order went through on that month and no outstanding debit order on my side. Then they say it must be an issue on their side, then again I am transferred to a different service consultant then I have to start over to provide details. I have also sent a bank statement as evidence yet no resolution has been reached nor a response. Secondly they noted that I have a active 3rd contract sim which is active. When I ask if where is it being used no one knows , so basically I am paying for a sim contract that I don't know of or have. When I tell them to cancel it they are sending me to all different customer service lines with no assistance. Also they want me to pay for a cancelation fee for a contract that I do not have or never used.