Stupidity like that does not even warrant a response.
The kid was on the phone outside, alone during lunch hour. That was on his own time.
His father was dead, he lives with a guardian. His mom, probably the most stable influence in his life was on a rare phone call from a freaking war zone a half a world away. Some stupid chip on her shoulder, overzealous thug of a teacher with no sense at all comes and rips his phone, his property, from his hand and tries to march him off to see the principal. The stupid principal has him so tied up in knots that he misses her next call too.
OK, I'm done ranting now.
I guess the school rules apply to everyone but this young man.
What stopped the kid from walking straight into the principles office, with the line connected and getting approval from the principle to continue the call.
Obviously his Mom was still on the line when he started his defiance. I sure would have hated to hear my Mom's response had she heard me talking to a teacher with disrespect.
Probably handled bad by both parties.