Unstable ADSL line and Poor Technical Support

I have logged calls with Telkom from about 15 January 2018 regarding my unstable ADSL line. The technical team even suggested me to reduce my speed to 2m speed to stabilise my line. My technician came and check and could not resolve or give a reason why my line is unstable. My last call was on 12/03/2018 and ref number is ********** 18 and telephone number is ********** 220. Please may some assist because it is affecting my productivity.