I have had a real bad mat from a top knot before too, really bad but just sat down and worked with it until I got it out...first pulling it apart gently with my hands...this takes some time, and then taking little sections of the mat and slowly working out each piece of mat that I pulled apart....it works but takes time and patience. It works better for me though to do it dry, then when I am almost done spray a conditioner on it and finsish combing it out. Hope this helps
I would only cut it as a last resort.