Previous homeowner cut the cord off the upflusher. What can we do.

He may have done that for a reason. First try to insure that the toilet actually works by connecting temporary power. If it operates correctly then remove about 2" of the outer insulation on both cords to expose the black, white and ground. Skin each wire, 6 of then, back one inch and wire nut then together. Black to black, white to white and ground to ground. This splice should not be in a location where it can ever get wet. I would do it in a water tight junction box.