But I have the Pin set high if the button is not pressed. so Why it should not be counted when its low?
600ms is because I don't want to allow the button being pressed that frequently.
It seems to me like you want to count once for each switch press, regardless of how long the switch is held down. If that isn't what you want, forget I said anything.
Still, the 600 millisecond delay is not for debouncing, so your comment is wrong.