While I agree the FA should have asked to have the question repeated, I think it should have been pretty clear to the pax that the FA misunderstood, given her response. In that case a "ma'am, I think you may have misunderstood me. My question was..." may have solved the problem.

That said, in NO WAY do I think this absolves the FA of blame in this situation nor do I think the outcome was in any way justified.