I've just started learning Japanese, and I'm very confused by how 困る is used. For example, we had a sample dialogue that went (in response to some bad news):
I'm confused because since the news has just been delivered to B, why wouldn't the imperfective 困ります be used instead? My reasoning is that B "has a problem" now, but there was no problem earlier. Even if there was a hidden problem earlier, it's still there now (i.e. not over/completed yet).
I asked the instructor, who said something about the problem itself occurred in the past, so either one could work; I'm not quite convinced because I thought ~ました referred to completed occurrences only.
Is there a clearer explanation for why they used the perfective aspect? Or is my understanding of 困る incorrect?