Opened 1 contract but paying for 2

I am being billed for 2 contracts when I have only taken 1.The Fourways Crossing Telkom store loaded another identical contract on to my account erroneously. The number *** is not mine. I have asked them to produce the contract for this number. They have not been able to do so. The case was logged 7 months ago and no resolution. Telkom Case number ***1