Airtime and Data Depletion

Yesterday I had connected to my work wifi to update my software. Thereafter I realized that all the airtime and data I had had vanished. I loaded more that also vanished. When I got home I called Vodacom and was told that I had apps running, which I checked after the call. I then made sure that all apps and auto downloads are switched off. Thereafter I loaded more airtime and data, that vanished as well. So in one day I loaded about R90.00 airtime and about 200MB of data which vanished and depleted in no time. How is that possible? Especially when I had no apps running or any downloads. Its unfair and ridiculous how much one spends on data moreover when it disappears without any explanation. I would like to have my data back please.