Worst treatment from cell c

Since 11th og July I have been having problems with cell c. Its been 6 months and still no solution. My home router I bought wasnt working from the beginning. So I let them know and they kept updating the software and even told me to do it myself. Which I did. Which last a few hours then stops working. So then I let them know of my problem and they tell me to book in my router. Which I go do. Willingly. I ask for my contract to be cancelled and then got told that they cannot cancel it because it has been fixed. All this while im still being billed for a roughter that I dont have. Again I get told that they will let me know when my router is done. Its almost 3 months and its not back yet and guess wat????!!! Im still paying for it!!!!!!! So if cell c would be so kind to please cancel this contract as they are not fullfilling their duties or keeping their customer happy. Please cancel my contract!!!!!!!!!! Its been half a year already.