Cell C overcharging me on R99 contract

<p>I signed up for a R99 contract w/ Cell C 5 months ago, with the agreement being that I get 5GB peak, 15GB offpeak. I was charged R99 for the first month of the contract, and have been consistently charged R325 since. I called the call centre on Tues 31 Jan, and was told that the billing department would return my call or contact me asap to resolve, and there has been no response one week later. I would like to have my money back, Cell C.</p>