Taken for a ride

I Have the Problem with my Billing I think<br> I'm being over charge cause I don't even use<br> my phone to make calls but this months bill<br> came to R508.55 and I don't know how. Cause<br> I only use Bundles on that phone and when<br> they finished I switch it off. Please explain<br> as to how did I get to R508.55. And on top of<br> that I'm only Getting 200MB on my Contract.<br> At Altech Autopage.<br>