Blocking/attacking a serve

[steve_s]

I'm a new member here, so bear with me.

Rules 9.6.5 & 9.6.6 state that a served ball may not be blocked or attacked, but I'm confused by the caveat "However, the contact is legal, and the ball is not out of play until it completely crosses the vertical plane of the net or is legally contacted by an opponent".

So what if a player attempts to illegally block a serve, but fails to put the ball back over the net? Her teammates then play the ball legally, and eventually return the ball to the opponent's side. Is there a foul here? Should I call a net foul once the ball eventually crosses, even after a third hit? Or is there no foul because the blocker failed to put it directly back over? Seems like there should be a violation since the ball was both blocked and attacked contrary to the rules, but I'm not sure about if and/or when to blow the whistle.

What say the experts?

Thanks,
Steve