Telkom cancellation debt collection fail

I cancelled my internet account in Dec 2018 with the online facility. I followed the website instructions closely, and sent the document per request. I followed up with an e mail asking if the account was cancelled in Jan 2019, with no reply from Telkom. I visited the Telkom branch in Clearwater and they told me they will fix the cancellation. I followed up again with another e mail in Feb 2019. They handed the account over to Nudebt, and this company is also just as incompetant in getting the message through. They now placed me on Credit Bureau. I feel like getting a lawyer to sue someone for defamation of character.