Is this the same as line in the sand?

[LDUB]

Last night I called a youth softball game. One of the girls seemed to have a little of a problem. So she is up to bat, pitch comes in, catcher moves and blocks my view of the end of the pitch. From what I saw of it, it was a strike. I call strike, batter looks back and says "Are you serious, thats insane." I dedide to let it go. She ends up getting a walk.

Next time she is up, first pitch is about halfway up the torso. I call the pitch a strike. Batter moans, and takes her arm and signals to the height of the pitch. Right after this pitch, we realized the game was over because of the slaughter rule. Now I would have issued a warning to the batter if the game had continued. Did I do the right thing?