crazy data billing and no asistance

i was billed over R800,for 2 months for data usage on my account, i called vodacom to query about the billing and as usual they did their investigation and sent me an sms stating that the billing is correct as i have visited,whats-app,facebook,eBay and you tube,i called in to complain that i need them to send me the itemised billing showing which sites i have visited and how much they have billed me for those sites,they sent me list of dates and times with lots of numbers i did not understand,what irritated me was that its actually costing me more data when I'm sleeping than when I'm online,i told them that i was unhappy with the info since it still doesn't explain my usage,i requested for url info,which they sent me the disclamer that says the info on the url might not match or explain the billing info and that i will get the info telephonically or verbally,the only way the info can be provided to me is if i go to the government. So they over bill me and they cannot prove how they billed me,people need to watch out vodacom is ******** people especially when u are on a contract.i still have 18 months for my contract to end,we will see about that