Out of bundle charges before bundle data is zero

I need to understand why Vodacom decides to charge me out of bundle rates whilst my data balance is not zero. I took a screenshot of the account on their mobile app, where by bill had shot to 3k and yet i still had about 20Mb of data available. Now the call centre lady tells me I was downloading or streaming videos that takes up a lot of data and that I was on a contract and I can't use so much data in a day. Now is it Vodacoms business to what I view or download, even even I use the whole bundled data in a day. WHY CHARGE ME OUT OF BALANCE DATA WHILST I STILL HAVE DATA BUTTLES EVEN IF ITS 20MB<br> I did call Vodacom on the 20th of January 2015 to put in a complaint and I was advised a consultant will call me within 15 days, up to today no call nor feedback from Vodacom