Mine worked great for about four hours and then all of the sudden began to glitch on me it would play for a while and then the game would lock up at first I thought I had created a driver conflict when trying to install my controller system I went as far as to purchase a copy of Windows 10 to try and resolve the issue but it just got worse so I uninstalled Piplay and installed the Oculous Rift software I began to get a repeat message HDMI disconnected that’s when it became clear now the Headset is unusable the slightest movement and the HDMI disconnects.
Buy a £1 new HDmI cable and live life again 
It’s hardwired into the headset genius.
Make sure your monitor and pimax both connected to you video card. By the way, you can contact the skype: support@pimaxvr.com to ask for help.