I was in a similar situation in an international flight ,sitting in front of a guy who had mistakenly transferred 10 bucks to another guy’s account, and was now calling him up asking him to reverse the transaction.
Other passengers asked him to switch off the cellphone but he didn’t.
Plane was about to take off , and the desparate hostess ( she was strapped for take off )asked me ( in aisle seat) to tell him to switch off .
I told him curtly to shut up and and that aircraft safety is more important than his 10 bucks. Only then did he switch off.