It sounds like the window motor and/or the window regulator (the arm/lever contraption that the window sits on) has become separated from the door. I bet if you take the door panel off you will see that a rivet has broken, or a screw is missing, and the motor/regulator has become separated from the door panel.
It happened to me. I had to reinstall the regulator and motor to the door panel, properly.
If it turns out the mounting holes in the fiberglass door are enlarged and too big, you can use a little fiberglass-friendly epoxy to fill the hole before drilling a smaller hole back into it, or you can try to use a longer bolt/nut and large fender washer combo to get the bolt tension spread out over a larger area.
A fix for the motor being slow and not working, if it's still an issue after fixing the regulator, is here: