LGP under the basket ?

[Zoochy]

I worked a 2-man game last night. Had the same play. I am lead and Trail is just inside the mid-court line. As the Lead, I am moving across the lane area to watch the baseline drive better. The only thing different in this play is the defender desides to turn away (like she is boxing out). Double whistle. Since we pregame double whistle. Play is coming to me, thus I take the call. I call charge.
After the game he disagrees with me stating that the player does not have legal guarding position because her back is now towards the player with the ball. I say defender did nothing wrong and player with the ball runs over the defender. Then he barks something about the restricted area. We agree to disagree.
Oh well.....