Have had good luck running the line under hot water in the sink and tapping the knot with a hammer. Smash it flat and then stand it on edge and smash it. That should undo or loosen the knot.
If your bar is like the one in the video; you could drill off the rivet head and remove the bar end to get to the insides. Replace with same size 3/16" or 1/4" rivet. Harbor freight has the big rivet gun for 1/4" if needed.