TOi Technologies lack of Stable Line speed

For 5 months I have had the most unstable service I've ever experienced. R3000 for installation of equipment that the dish had to be replaced 2 months ago. Paying R699pm for a 6mBs line that never supplies a stable 6mB for more than a couple of minutes. The owners of the business are adiment with all tests that the line is stable but on proof of test speeds from 3 different devices I get speeds as low as 0.02mBs and ping rates of over 3000ms. I would like assistance to get my installation money back so that I can change ISP as they do not compensate on their bill for lack of quality internet speeds. We are forced to pay for a 6mBs line supp**** when we at best get 1mBs for an hour or so. Their service will not improve, neither will there God like attitude towards apparently good service provider.