Disgusting service!

I received my latest bill and to my horror my data account is R4062.50 Reading through the account I see that next month my data charge will be R7323.38. I have been a loyal client of Autopage for over 8 years and my total accounts average is R1887.00 per month. I emailed and called Autopage to ask for a print out of my data lines itemised billing. They sent me my cellphones billing. I mailed them my entire query in detail to which they responded that I only have a 2GB package! I'm very well aware of what package Im on. I need help finding out what happened as this is definitely incorrect. No one wants to help!!! but rather pass the buck. It seems that as long as your debit order goes off they dont care... CUSTOMER SERVICE is non existent. My contract is coming up for renewal, I guess I know who I wont be going with.