Worst Service Provider

I am disgusted with service received from CellC over the last 12 months. They offered me a 10G data package for R99 per month and I am paying R150 for a 20G plan. I queried this and was told that it would be rectified 2 months ago. I cancelled my Getmore subscribtion a month ago and this service cost is still being added to my monthly bill. I have tried numerous times to contact the number provided for Miassist for cancellation with no success. When contacting CellC they only tell me to contact the number provided. Is it possible to get any service or assistance from this company?