Telkom is the Worst

I have tried since August to cancel my Telephone line with Telkom. I phoned, they mailed me the forms to complete, which I did immediately and returned to the email address they supp**** me with. The mail kept on coming back with the message the mailbox is full. So after a week I went to a Telkom branch and took the form with me. The branch could not assist me. The lady phoned the cancelation line and handed me the phone to speak with a assistant. She gave me a different email address to use. I forwarded the cancelation letter to the new address. Then I got a reply that I need to give them a date that I would like to cancel. Ridiculous as everything was completed on the form. But I did just that. And GUEST WHAT? THAT WAS THE LAST COMMUNICATION. Friday I received a sms that I need to make a payment immediately otherwise I will be handed over for collection. Without receiving a account or any further communication. SO WHAT WOULD YOU SUGGEST I DO?