Cancellation of Telkom account

I canceled by Telkom phone line in February of this year and had my number migrated to Switch Telecom. I have continued to receive accounts from Telkom, despite having visited the Telkom Shop twice to go through the process of trying to cancel my line again. I have also tried from the website and even received a cancellation request number of ********** . Now I have received an SMS to say that my account has been handed over to NuDebt collection. I am sick and tired of dealing with such an inept and pathetic organisation. Please get your act together TELKOM. You have no right to deal with the public if you cannot handle such minor issues as cancelling someones account and stop billing them.