I want to believe i was over charged for Data

Hi Vodacom<br> <br> I'm a bit surprised with my bill this month , my data is close to 18K and I also bought the 2GB for 7 days bundle at 99 ZAR seven times plus another half a gig and of data on the same promotion plus my monthly 800MB per month as part of my contract . so if my memory serves me right Vodacom charges 3K per GB or 3 rands per MB of data out of bundle as they would like to call it . so my question is ?? how is it possible to price some thing at 3000 rands and 99 rands for the same product not sure what the pricing promotion works out per MB but that is very affordable . 18K would mean 6 Gig of data out of bundle how is this even legal ?? that 6GB can be less than under 300 rands and the same product is 18K . in the same country from the same customer . every time I realized I was out of data I would buy another promotion but what when would I have used up the other 6GB<br> <br> I would like for Vodacom to explain this difference and also for Vodacom to include dates on my promotion purchases so I can see when and how the 6GB was consumed .<br> <br> Thanks and Regards