Bad service and made up data usage.

I have never used excessive amounts of data, not on purpose or by accident. On the 20th I was out running errands (not sitting on YouTube), and supposedly used over 500mb data which is more than I use on an average month. My phone did not update any software, stream anything or do anything that required that much data as It has been set to only do so when on wifi. it has never done this before and there is no evidence to show that it has happened now. Not only have I been charged for data I have not used, vodacom has also allowed my account to go +R150 over its cut off. I have previously experienced problems with vodacoms lack of service, and have now again. I made a call to customer care on the evening of the incident to enquire what was going on, but gave up as the agent lacked intellegence. I then tried again the following day where I was told she couldnt do anything about it(later to discover she could), so out of desperation I went to vodaworld where they submitted an enquiry(why couldnt this have been done through 111?). I have since been contacted again, one who was friendly and another robot. no one gives me info to contact them, no signatures on emails, customer service?