Haunted by Cell C

Cell C giving me sleeplesa nights as always... So my contract lapsed in July, however i was not aware that i have to call for cancelation if I'm not willing to make any upgrade, so today i received my bill and noticed that my account will still bw debited although I didn't make any upgrade so i was advised to call and cancel the contract, which i did however I'm told that i need to serve 30 days notice before i can cancel the contract as I'm still receiving benefits i was not aware of any benefits since i haven't even been using that sim card, now on the 15th on September i will pay for the contract that has expired, and again in October... This ia my hard earned money we talking about here and Cell C never even bothered to advise me on that cancelation all they do is to call me offering me upgrade .... Just when i thought i had cut ties with Cell C now this happens