Airtime Billing Ridiculous

I had bought R180 airtime of which I wanted to purchase a 1gig of data.<br> Not even 2 minutes later I had too little airtime to purchase my 1 gig of data.<br> In the space of approximately 6 minutes maybe less, my account had only R59 left.<br> I had no running apps at the time of purchasing the data and the only thing on which my background data was not restricted was e-mail. Vodacom cannot give me an account of what my airtime was deducted for, save that it was for internet which was not even running at the time of purchase. furthermore, I find it almost impossible for R120 of airtime to dissapear where the only app that could run in the background was my e-mail.<br> Please advise what would have taken so much airtime as no one else could give me an answer.