1 GIG data in Half and Hour?

Vodacom, we seem to have the same problem every second month. In the space of 30 minutes my data usage was almost 1 GIG????? There's no point in me calling your office as I will just be bounced from one person to another so please get one of your consultants to call me regarding this problem.<br> <br> I also requested a letter from your accounts department advising the cancellation amount for my cell phone contract. This letter has not yet been received and I would appreciate someone getting back regarding this as well.<br> Thank you