Why is my Vodacom data suddenly disappearing?

What is going on with Vodacom and their data? How are our 30G being depleted in only 15 days when all we use data for is social media, whatsapp and email?

Today on the 15th July our data (from our Vodafone ****le) switched off. I called Vodacom to find out what the problem was and they told me that the data had 'run out'. When I enquired further, they put me through to a 'specialist' who also couldn't tell me what is going on. I asked for a breakdown of data usage and they said the data was being depleted by 'updates' but they couldn't give us exact figures. When we checked our phones to see how much Wi-Fi data we had used, it said collectively less than 7G since the 1st July. So wjere is the rest of the data - 23G?? Vodacom, please explain to me how you can justify 30G of data being used for whatsapp, gmail and scarce use of social media. We don't watch videos, download or even use YouTube!!! We have had this ****le since December 2017 and have updated our phones on numerous occasions and not once have we run out of data until last month and now again this month? What is going on? Why can you not explain where all the data is going? We aren't connecting to any sites to download ANYTHING !!!

I have heard from very many people who have had the same problem. Our family have 6 phone contracts with Vodacom and we are immensely angry about this. Do we need to cancel our contracts and move to another network???