Unresolved query going back to March 2015

At the end of October 2014 my contract was due for an upgrade. My husband phoned Autopage and the phone was upgraded. The consultant he spoke to told him that the data would be charged at 19c a megabyte. But for the past 6 months we have been overcharged by 500%. We have phoned Autopage countless times but to date no solid response or correction on the overcharge. My phone gets suspended regularly and then we have to phone and get the line unsuspended. We pay the monthly contract fee but no more. We are at the point of moving our contract to a different service provider. I have had this account since 2001 and I would've expected better service from Autopage.