3G DATA AND HIGH BILLING

Is anyone else having issues with their 3G data being depleted when you're not even using it?<br> <br> I have wifi in my office and wifi at home, so I barely use 3G data in the week at all. When I do, it is just for emails and WhatsApp messages for maybe a few minutes whilst out at lunch, which hardly uses any data.<br> <br> A couple of months ago, I noticed that my 3G data was being used up, even though I was hardly using the phone. I even topped up 100MB, went into a meeting (when I didn't use my phone at all), and when I came out of the meeting the 100MB was used up?!<br> <br> I decided to start taking screenshots on my phone to trace it. I reset my 3G stats and loaded 100MB data on Sunday. I have now just received a message saying my 3G data is used up, but my 3G apps show that I've used about 16MB.<br> <br> Whilst the individual apps total a usage of 16MB, the total says I've used 95MB. How is this even possible when I'm on either my house or office wifi 95% of the time, using 3G data for just emails or WhatsApp messages on the very rare occasion?!<br> <br> They've now stung me with a huge bill, which I've had to pay because they disconnected me. No one at Vodacom bothers helping when I call them to question this...