DATA charges WRONG

in January my contract was still a 2 GB top up, this month my contract is already 3000 rand... I have phoned since Monday, all my calls get escalated, I was promised yesterday some one will call me before close of business... NOTHING. YOU are in breach of contract, if this doesn't get solved today, you can come fetch your device and cancel the contract that YOU are breaching.. SAD that I know 4 other people you are doing the same to, also no one can explain how I used to use 3 GB of data each month, and this month I used it in 2 days. USELSS SERVICE , BAD PROMISES. and NO RESPONSE ... OR you are so USELESS that you are trying to call me on my DATA number