Unknown charges

Around 20 March, I checked my balance and I had around 5GB day data leftover, so I stopped using my data device during the day for the rest of the month. I called Vodacom (Ref:S3-82G2K-KYIU7) because of a high charges and was told that I was charged for 7GB out of bundle rate. I was sent the excel itemised billing (which is not very customer friendly), and the 2 main charges was on 23 March for what seems to be ~3GB data. So this doesn't add up for the following reasons: 1) My balance on 23/03 showed I had enough data but was still charged, 2) I don't recall using that much data especially knowing that my balance was quite low, and 3) The Vodacom call centre said that I was charged on the 23 March for a call that was made after midnight - but the excel sheet I was sent doesn't match what I was told, and if I had made these data calls after midnight then I shouldn't have been charged for it as I had enough night owl data at that point. I'm highly confused with the different 'stories' I am being told and going around in circles to clarify this issue. Highly disappointed with the lack of professionalism and the call I received from the Technical dept on 27/4/15. Disappointed