Collision and re-calibration Fail  

Collision and re-calibration Fail

The print head of my i3 MK3 collided with the model several times. Now it fails XYZ calibration ( Z axis specifically) while using the calibration wizard. It successfully calibrates the first point at 0/0/0 corner, but then drags the paper sheet while attempting to calibrate the next point at the corner of the bed. Have had to shut it down three times now, and not sure what to do.

...This occurred while attempting to finish a print, using a roll of Amazon basics PLA ( which was wound in such a way that it has been repeatedly tangling and  binding up while the print has been running). When the filament binds I can hear the scraping sound, and have been just quickly pausing the print / untangling the roll / restarting the print.

The last time that I paused and then restarted the print, the printer appeared to have lost it's calibration. It repeatedly attempted to "re-home" to 0/0/0 while pressing the print head down on top of the model. It did this several times before I shut it down....and realized how damaging this is.

I am looking at this page in the Prusa Knowledge base ( link below), but it's a little above my head. Do you have any recommendations?
https://help.prusa3d.com/en/article/xyz-calibration-mk3-and-mk3s_112351

Thank you