Inconsistent billing

<p>I have a tablet on contract with vodacom and every single month i recieve a diffrent amount taken off my account and i make sure i dont you data outside my cap as i have wifi at home and then switch over to that and every month im being billed different amounts i recieve a "statement" from vodacom on email every month but vodacom are so cleaver they put it in a format that it cannot be opened by my computer, tablet or my cellphone which im sure is on purpose in jul i was billed R605 aug R526, sep R338, Oct R338, Nov R342 and now in Dec a Crazy R726 and i know i didnt go over my cap as i only got a message on the 30th to say my cap was depleted and then switched to my wifi i want this sorted out and for the record i quiered this before and you guys had someone respond to me who had no clue what they were talking about. if this is not sorted i will not be upgrading my contract in january.</p>