Billed for Data that was not used

For the past 6 months (or even longer) I have had an external data package with another service provider, Afrihost. My cell phone bill with Autopage has always been in the region of R425. Last month I was hit with a bill of R1200. For data that I did not use. I have the itemised proof from Afrihost that I was in fact making use of their data. There is no possible way to use data from Autopage simultaneously. (You physically need to switch over) Each time I log a call - or send an email to follow up with my issue - Autopage \Close the query"without coming back to me on the matter. I have called 3 times today and keep getting cut off. Clearly Autopage don't want to deal with this. I am so so furious now. I am very close to leaving Autopage after something like 10 years. TERRIBLE service! This is *****. I need my money back. I am ONE UNHAPPY CUSTOMER!"""