Overcharged for contract that I'm unable to use!

Cell c has pathetic service and *****ed. I had a contract with them for data of which I was paying about R136.00pm. Few months before end of contract it didn't not work. I called them to resolve issue, but was not helping. Then i asked for this contract to be cancelled. To my surprise I have been charged even more for something I had nt been using for months!!.

When I called them now to cancel again., was told it will only be canceled by August, which means they still gonna charge me again for contract that I'm not using. I was so ****ed shame.