No Ways! Data Billing sky high!

Wonderful to start a new year with Vodacom debit order over R8000 bouncing.Last invoice 31 December 2015. WHAT? HOW? WHY? Spoke to 2 customer care consultants (why they are called customer care only they will know as they don't care about their customers). Log S3-GJH94_LOPM. I have a 3G that is 5Gig a month and now its over R3000 billed due to high usage, strange as the data ****le is in the drawer most of the time as we have wifi installed at home. The data is only used when the wifi is off and thats normally once in a while and only to check emails. Definitely not over R3000 worth of emails! I'm not happy about this and refuse to pay this ridiculous amount. I've seen the itemised bill that the actually charge you for R18. What and how i don't understand. but the dates and times on this hectic billing i don't understand. 29 November over R1200 on 21 November over R1100. What in the world must ghosts be downloading? If you have a look at my acc you will see that my overhaul bill is normally R4000 - R5000 NOT R8000. The month before it was high but that was due to usage that I know off, shock to the system in anycase but I paid it. This is unacceptable. Urgent attention required! tx