Data day light *******

I loaded 500MB of data about 15 minutes ago, please note that none of the settings on my phone have changed. In less than 15 minutes i get an SMS notifying me that I now have only 138MB of data left. When I call the Vodacom call centre, no-one is able to explain to me what the issue is. <br> <br> This is not the first time this has happened and each time Vodacom data provides me with a report that they are unable to explain to me. Further to the above, they claim that apps that I don't even have downloaded on my phone (i.e. Pintrest) are using up my data. <br> <br> My phone has been in to both Vodacom and the Apple store for analysis and each time I get the same response that they are unable to advise what the problem is. <br> <br> It frustrates me that even despite paying Vodacom for my contract, they are unable to provide me with a logical explanation - all i keep getting are excuses and reports that no-one can decipherer.