Unable to Cancel my account for 4 months

I'm not sure how many time I have to message you people. In October 2015 I sent a cancellation form through to you from Centurion Branch. I've been waiting for the line to be cancelled ever since. I even had the cancellation form sent from your branch in Tygervalley again in November. The account is still not cancelled and I've received another bill, which I am not paying. I've sent the information countless times so please check your inbox for our previous communcation. Please cancel the phone number - *** - as requested last year already! If a cancellation form does not cancel a line, then how do you cancel a line with telkom?