Charged huge amount for data usage

I received an amount of R2100 for my MTN account. I immediately went to Kenilworth MTN to ask for a detailed report on my bill. I was informed that I have a top up account on my data account of 2 gig per month. However at MTN data base it is picked up that I have an open line. The consultant, Hieshaam was very accommodating, and promised to call me back as he lodged a dispute on the system. This was 2 weeks ago and I received no feedback to date. I then went back to Kenilworth and I was told my another consultant to go to Blue Route as they will be able to give me more info as KC is a franchise. At Blue Route, I was told that I have an open line and the consultant, Waseem (who was very helpful and forwarded my itemised billing by taking a snap shot) informed me to call 1555 for further assistance. I called 1555 but I was told that this number only deals with internet problems and not account enquiries. I called 808 and was put on hold for 30 minutes. I now do not know what to do or who to speak to about my bill as it seems that no-one can help me. The charges on the itemised billing does not even show a duration, so I do not know how these charges were calculated.