Breach of Contract

<p>I took out a router contract with cell c and the agreed amount was R130 for 4GB of data , 2GB during the day and 2GB at night , in december I kept on checking my data and when it reached 0GB I was cut off from the internet so I placed a call and requested that they add 100 Mega bytes and they charged me R21 , When I received my January statement I was surprised to see that I have to pay R679 , when I phoned and enquired about it they told me because I had an open contract so when i used the internet they were charging me , This was never explained initially to me and if it was I was never going to agree to the contract , I feel this is a smart way of cell c to rob people off their money , I cant afford that amount thats why I settled for R130 in the first place , I dont understatnd how someone can use so much money on the internet in a short space of time and how Cellc hides the small details like open contracts , how they charge if you are out of data , why no notification is not sent to users if they go over the limit etc , please help is this regard because I regret taking the contract and I feel vanurable as a customer.</p>