As the high-schooler rackets flow in(first season stringing for me), I got a couple Prince O3 Speedport Blacks in. Both had mains broken at the top, and all the strings were rubbed thin where the kid obviously drags the racket on the ground. The strings actually stick up above the guard. Is this a flaw of this racket or will replacing the guard get the strings back into a protected groove? They are both so worn that I have no idea what new looked like. Where do you guys get the replacements? I couldn't find at TW website.