I spend half my day (or what feels like it) telling people what they did "wrong", i.e. what they did that led to whatever they experienced that they didn't like. The trouble is that these explanations are expensive: it takes time and energy to track the specifics, deliver the information in a clear enough form that, proof it against possible misunderstanding or unintended offensiveness, and then go back-and-forth with the user when the information isn't clear enough or lands the wrong way. It's impossible to do a satisfactory job of this in every case, even though one wants to—the only option is to approximate.

Since you've mentioned twice that you didn't get an explanation, I'd be curious to see the case that you didn't get an explanation about. Is there a link? Usually when people remain upset about something long after the fact, it's for good reason.