Unexplained Charges

I called Vodacom on the 3rd December 2014 to enquire about a premature upgrade as I had dropped my iphone the night before and it smashed the screen. Basically I have had NO USE of my iphone and micro sim as my spare phone is a old blackberry with normal sim and airtime. I received my bill in January for R2500!!! I called again to ask how this can be has I have had no use of this number. And my micro sim is safely in my cupboard the whole time. I was told that my \children"or partner might have taken it. I said to her I can see it in my cupboard. She then said i must request itemised billing"