Unresolved Z-Axis Problems

I got my Robo 3D +Plus yesterday, and I got it all set up. Everything seemed to be in order, but after starting my first print, the auto-calibration thought that the Z-axis was about 10-20mm lower than the print bed. The x-axis chassis and extruder mashed against the print bed and popped off of the hex nut on the left threaded rod that controls the z-axis movement. I isolated the software problem that was going on, but I'm unsure of how to fix the hardware side of things. The only solution I can thing of is moving the chassis to the top of the threaded rods, screwing the hex nuts off, putting them back in place, and then moving the z-axis back in place via matter control. Is there an easier solution that I can't think of? This is my first personal 3D printer, and I don't want to risk damaging any components unless I have to.

EDIT: Since I received a lack of help, I just took the whole assembly off of the threaded rods and put everything back in place.