last to touch - first to touch

[rsl]

At a high school camp with NFHS rules.

A1 has control of the ball in the frontcourt. B1 knocks the
ball loose. A2 knocks the ball so B1 can't grab it, then chases
it down in back court.

I whistle back court violation. First one I have ever called on
the "last to touch - first to touch" rule.

Coach yells at me. At next time out, D2 evaluator tells me I
messed up because team control ended on B1's tap. I say
"yes sir" to the evaluator and smile.

4-12-3 says team control continues until opponent secures control.
9-9-1 says this is backcourt violation

What good is being right if nobody knows?
Or, did I kick this call and I am still clueless?