Cancelation of contract and still problems

I canceled my Vodacom contract for my cellphone on the 23rd August they provided me with a quote which I paid for. 1st September the debit order went off only for my laptop. My statement for the 10th month comes through and they have included the cellphone which is on prepaid. I am utterly disappointed with their service, if I did not have issues with canceling the contract they still choose to debit my account with the phone which is on prepaid. When I called for assistance the response was that I did not cancel my contract on time, yet all documents were sent to cancelation. I cannot explain the time that I had to spend on running after Vodacom to cancel and now again on the billing. Candice