yes, I am with Scott, replace the lines. Chances are that when you do get the nut to turn, the tubing will turn as well. When this happens you have to replace the line. I also use a 6 point tubing wrench designed for that purpose with the cut to slip the tubing through as described above. I never use a regular open end.I've always replace lines in stainless. The new owners never have the problem again...lucky them.
