Incorrect billing and terrrible customer service

I have been incorrectly billed for the past three months. I've sent countless emails with no assistance whatsoever. I am now paying for peak gigs that I have not actually used. Every month instead of resetting my peak usage, it's just continues from the previous month. I'm now at the point where I'm paying triple the amount I'm actually using. I have to pay my invoice every month otherwise I don't get acccess to my off peak data. I will be canceling my Sim this month and not paying RAIN a cent until they attend to my query and balance my invoices from the past three months!!!