Data consumption unexplainable

I have an iPhone 5s.<br> I loaded 1GB and in about 15min it was down to 600MB without me even using my phone for anything out of the ordinary.<br> Within an hour my data was finished! I checked ALL my apps which have been off the entire time. I then loaded 300MB which also got depleted within minutes.<br> I then switched off my data, only to use it when i need to read my WhatsApp messages. I had to load another 300MB of data. <br> I called vodacom only to be told to turn off all my apps which were already ALL turned off! I called again later.<br> My query was escalated and my query logged witht the data investigating team. They called me within an hour saying there's an https site running on my phone and I need to go to my nearest iStore to have it checked out.<br> They loaded 500MB data for me which had to be kept off.<br> I went to my nearest iStore, the lady checked all my apps and they were swtiched off excpet for one or two apps. THERE WAS NO HTTPS site running as claimed by vodacom and the lady at iPhone said those apps that were deactivated by her COULD NOT consume ALL that DATA<br> I called vodacom again only to be told the matter has been resolved. THERE WAS NO HTTPS app running on my phone!!!!!