BILLING ME MORE THAN WHAT THE CONTRACT SPECIFY

I have a TOP UP contract of which I am paying constant R249 per month. (See my records for the duration that I have the contract). Suddenly billed almost R1000 this month. Why? for data. When I called to esquire you say all calls recorded, so prove when did I uplift or say you can bill me more than the top up rate. When did i open the contract to be paying more. I use a a uncapped rooter at home and at work. That is why my contract was for a top up phone. I do buy more data or airtime when required. I now visited your shop in East Rand Mall 3 times. I phoned MTN ********** four x 4 times on 27/09/2017 spoke to operator Makolsi, Elroy, Risheed ,Deneo Maome and is still waiting for a manager Mohlake to call me back ********** 183. MTN I tried to contact and resolve my complaint but now noticed what I got to do with. No one there is willing to assist. Bad Company. Bad Customer Service. Nothing good about you. Rather cancel and join Vodacom.