Says I used R14K of data for the month of May!!

Phoned the call centre after receiving a SMS to say there is abnormal usage of data on my phone. Logged a complaint and received a reference number. 1. My phone line has been blocked. Was told that if it is not blocked I accept the charges for the data. How must I communicate for business and personal matters? 2. Why was I not phoned earlier if there is abnormal usage? My average account should be around R2,000 per month.<br> I urgently need an answer to what is wrong.