VERY Poor Customer Service by CELL C South Africa

I have a 24 month contract with Cell C and the last months have nothing short of disappointing. I am being charged to date more than double the amount for which I had signed up for and have been consistently told that I on a "discounted pack" and the discount depleted. While my contract clearly states I pay R289. for 24 months and am now paying R700+ for data I barely even use anymore. I demand a full refund of my monies owed by Cell C.