I'm not sure if there is a definite answer at what to do when you become chicken blocked. I play Arthur and the moments when I go into Lv. 3 X-factor with Arthur and start doing jumping S to get a good hit confirm and the opponent is smart enough to just jump back and block, there's not much I can do to counter the situation except for doing a throw attempt(which is pretty risky in of itself). Same thing applies with Vergil's helm breaker or any other character with a good vertical move. So is there anything I can do about it or should I just back off when they start doing it?