Airtime and data disappeared without being used.

Loaded 250MB and R30 airtime at about 13:30 and three hours later (at abut 16:11) nothing was left. The problem here is that in that time I was driving didn't make a single phone call had 2 apps running which one received 3 messages (whatsapp) and nothing was done in the other (discovery health app). Vodacom tells me the billing is correct the problem is that I'm using an IPHONE, I know my usage and I always switch off apps when in not using them. There is no way I can finish 250MB and airtime in 3 hours with 2 apps using data and the phone not being used at all. No Vodacom I'm not talking about the data I loaded on Saturday I know what I did with that I'm talking about data used today 28/03/2016. <br> 2 apps finished data and airtime in a time that the phone was not used for anything not possible!!!