Telkom not cancelling the account

Since April I'm trying to cancel my account with them. I have all the e-mails and proofs that I send each and every month asking for the cancellation. Last month they told me that the problem was sorted and I should not have to pay. Now for my surprise I just received an invoice and when I call to understand I receive the information that once that the service was only cancelled in November I will have to pay for the time that it was active. How is it possible? I'm asking since April to have it cancelled and now I will have to pay? I'm not living on the place where it was installed since April and because of a Telkom problem will I have to pay?