Telkom not cancelling line..

I havr been trying since May 2018 to cancel an adsl line with Telkom. Everytime I get a case nr I also get a sms a few days later saying case is resolved. Just to find out the following month that the line is still not cancelled. Now my existing line that I am using is suspended due to the unfair billing of adsl line. I have phoned numerous times.. Sent a lot of emails and I am just not getting any feedback. How can I get a positive response from Telkom.