Data used up in less then a day.

It is 3 months now that I am out of data in less then 3 days. Nothing is connected to the router and Telkom said on there side there is no problem and they can not help me.My case number ********** 4. When I phone in and demand that the manager of the service provider must phone me back he/she never phones back. I want to cancel that contract and not pay anything ekstra because for 3 months I do not have data and it is my problem and no after sale service that is what Iam going to do. I also asked for emails so that I have prof that I had contacted the useless Telkom I never received emails only one and its like Telkom useless.