First try this method to get out of demo mode:
If that doesn't work, try pressing and holding the STOP button for at least five seconds.
Hi, I'm Russell, Expert at JustAnswer.com.
I think that the control console probably is defective.
It may need replacing.
But, if you try unplugging the Quadflex from the power - while it is On - for about an hour or more, or for overnight, then it might reset back to a normal condition and settings etc. in the console and the functions.
Also, consider how roughly it was moved. Might it have been damaged perhaps? or need a cable re-seated?
If it still doesn't work after holding the STOP button for at least 5 seconds, then check for a stuck button on the console.