Vodacom
Almost 12 x increase in my account

I try and manage my phone account on more or less R400 per month. Last month it increased to R800 and this month it increased to R3400 and if I check my account for this month it is already on R1080 (one week into month). If I however pull out itemized billing, it indicates that my account was R2761 and current it is on R280?
I have gone through to a vodacom store in order to query. I was told it would take up to two weeks to investigate. However my itemized billing indicates that each and every day for the entire month, my internet on my phone was used bewteen 00;04 and 04:58, every single day, for up to as much as 273 402.37 Kb. I am never awake at that time to start with.