Internet service keeps dropping

Since mid December 2017 I have been having issues with my Telkom line. It got to a stage where I had to call Telkom on average 4 times a day to "refresh my port" in order for my internet to work. I pay for a 10mbps line and I have never actually reached speeds anywhere near that. I did not complain as it was working. Since the issue started I have been getting speeds of 0.26 mbps or it completely drops every few minutes. The call centre and technicians have done absolutely nothing to rectify this issue and I am still being billed the full amount if not slightly more. This is literally **************** as I am paying for the "fastest adsl" and receiving pathetic service and absolutely useless internet. I have also noticed that my internet works perfectly for a few days when I threaten to cancel then it goes back to the same issue. I have no idea what to do from here.