R3000 in one day?

Yesterday I bought 1 Gig data on my contract account and my bill was about R1000. This morning I get an sms that the data is finished. So I log onto the mobile app and now my account is R4200??!!!??<br> <br> How can this be? Vodacom, please investigate and explain to me how I can be billed R3200 in one day.