backcourt ruling during a game question

[81artmonk]

hello again, I need help again.

During a game for the girls team I coach we had a backcourt or non-backcourt ruling that I questioned and need your help in explaining.

The opposing team came across the halfcourt line and my girl defended her well enough to slap the ball loose from her grasp and on the way down the ball struck the ballhandlers foot and rolled backcourt. The ballhandler ran backcourt and retrieved the loose ball. There was no back court call as the ref explained that there was no possession.
Here is where I get fuzzy. If my player throws the ball over her teammates head and the ball goes backcourt and my team gets the loose ball, that would be called backcourt?? right?? Well, where is the possession in that situation?? Was the refs call correct?

My assumption would be that it isn't about possession. Because if it had been touched by my team, as a tip or deflection, there isn't any possession there, so back court isn't called. So I need some explanation here please??? thanks