Sorry to hear about your issues. Their wiring is usually not good and the stepper drives not any better. I had one and first thing i did was dump the spindle, drive and all electronics. Only thing i kept was the main power supply and stepper motors.
Update 2/21/21....I bought one of these machines with the black box controller and the 1500 watt spindle back in October of '14. It has been run 2-3 times a week for a few hours at a time in a semi-production environment, milling 1/16" and 1/8" aluminum. I have no idea how many hours it has now, and gets pretty minimal maintenance. All the original parts are still working, although I have spares. There is no appreciable slop in any of the axis, and it still is accurate to within .001" or so. Almost 7 years, hundreds of hours, and untold numbers of parts milled, and still going strong. Best purchase I ever made.