MISREPORTING OF DATA USAGE

I got a sms notification in Jan that R894 is due end of January. I was taken by surprise since my bill is usually between R590- R640 maximum per month. I contacted Neotel requesting a copy of my statement. I noticed that the increase was on my data account and it had gone up by R300 i.e. I have used R300.00 worth out of bundle data. We have a 10gig contract. We are 3 adults using it for internet, email and the odd downloading of information from time to time. Then I received the new bill (which is due the end of Feb), this time however according the the bill, we have consumed 20gigs of data, my bill being R1358.55! I called the call centre on the 9th Feb and spoke with Katlego querying this. He said that according to the account the data was used. He advised me to change passwords etc since someone might have hacked into my account... I found it to be very strange. After back & forth with him I asked him to escalate the call since I wasn't happy . Ref no: SREQ*** was given. I changed the password & also activated a data tracker. It differs vastly from neotel's notifications. Joyce called me Tue, 10 Feb, wasn't happy with her answer either. Plse investigate! want it reversed!