Telkom ********** purchases

I received my monthly bill from Telkom and I was charged R99.00 more than what my contract stipulated. I then called telkom and was given ref no. This is the msg I received thereafter: Your query will be attended to. Your case number is ***8. A month later I have not received any feedback and still billed for more than what I signed for. Only myself and my husband have access to the wifi and neither of us have made additional purchase for data. Is tell on overcharging me, with the hope I will not take note or is the someone at telkom that has access to my account and is using for their own gain?