Xpress worst ISP, throttle our connection

We are currently on an upgraded line speed of 4Mb/s and our permanent speed is around 50-200 kB/s. Everytime we complain, they come out or fix the speed for that day, then back to slow speeds or no connection at all. I have recorded the speeds and they constantly throttle our internet. I am about to change ISP to a more reliable provider as anyone is an improvement over Xpress