Telkom cancelled line debt collecters.

It has been a few years, I think 5 or 7 years later. What seemed to be a simple cancellation has now turned into a huge mess and my credit record being affected. I had an ADSL line a few years back with Afrihost as my ISP. I did in no other way use the voice line as I had a cellphone and why would I use a voice line, but apparently I needed the voice line to get the data line which I did. It was probably about one year into having the service which I decided to switch to LTE as ADSL wasn't working for me, I cancelled with Afrihost on their portal and immediately cancelled my service with Telkom. I received the cancellation request was successful and so I paid my last installment and assumed everything is cancelled. The next month I received another statement which I went in to Telkom and queried what it was, apparently only my data line was cancelled but not the voice line and I stated clearly on my email that I want to terminate my services with Telkom. The consultant told me it's fine he'll sort it out, I paid this last said bill because I didn't want to make anything difficult as I myself works in customer service and know how it goes. I left everything in this consultants hands to sort everything out as he will be giving me a call. After I settled this account I kept on receiving statements and I would always call in and they'll say it will be sorted out. After a few months and all the back and forth and the bill now going from R0.00 to R2000 I had enough and went in to the Telkom shop again, I demanded this line gets cancelled while I'm in the shop and it was sorted. There was no activity on this line because no phone wasn't even plugged in, why did I have to go through all that to just cancel a line when the consultant could have done it the first time? I do not have any reference for this as this happened a few years back but I am still getting calls till today to pay up my bills and this is now the 3rd debt collection agency for this amount.