Shocking billing that never gets resolved

I am a very longstanding customer of Autopage cellular (decades). I got a new (upgrade) phone in January and upgraded my package to MTN 350. My monthly package includes 350 minutes anytime calls, 300 SMS's and 300MB data. This has been confirmed numerous times with Autopage as being correct and reflects on my monthly statement as the package I have bought. <br> <br> However, they fail to bill me according to this. They are billing me over and above my monthly package fee, for every single SMS and every single piece of data from the word go. They should only be additionally billing me for any SMS's that exceed 300 per month, and for any data usage that exceeds 300MB. Besides this excessive billing, they are even repeat billing each month. For example, my May invoice includes billing for SMS's and data that goes back to February and which has already been paid. <br> <br> They keep saying on Hello Peter that they have attended to the problem, but THEY HAVE NOT DONE SO. I am beyond tolerance now and ready to cancel my contract.