Pay for WiFi Speed I am not getting.

I pay R844.00 per month every month on time for a 5MB/s wifi. I seldom get 5MB/s down load speed, I am luck if I get half the speed. When you report the problem, you are asked to reboot the dish, reboot the rooter, test,test and test... the problem is never on there side, always on the client side. I have been told that adjustments have been made, it works for a day the slow speed again. When ever you mention that that other clients reporting are experiencing the same problems, the speed goes up. I feel they are unable to supply the speed I am paying for. When you work from home, slow wifi is the last thing I want to be concerned about.