Wow! This happened to me today. I won't go into that story, since there is a little animosity over it, but I had another voice mail one time that was pretty hilarious.
I had called a co-worker about an issue. She hadn't called me back, so I called the "hound dog" in her department, who happened to be her boss's project coordinator and former secretary. The folks who worked for this boss didn't want anyone calling the hound dog, because that meant that they would probably get in trouble with boss. If it took that to get them to do whatever was needed, then that meant that they weren't doing what they were supposed to be doing in the first place. So, a call to the hound dog, for those who made the calls, meant that answers would soon be forthcoming.
I had waited a few days to get an answer, and then I called the hound dog. Amazingly, about 5 minutes later, I had an answer on my voice mail from the offending party. I also had two more minutes of voice mail with her cussing and calling me several pretty nasty names. It's funny what happens when you don't hang up after you leave a voice mail message.
Fortunately for her, I like her. I listened to the whole thing, just because I used it as a bit of feedback for future calls and things like that. I thought maybe if I could learn from the experience, that would be something at least worthwhile. I deleted it, and then I called her back and got her voice mail.
I could have left her a nasty message, but I didn't. I could have forwarded her message to her boss, which would have been really bad. I didn't do that either. I just told her thanks for letting me know whatever the "real" message was in regards to, and that the next time she calls someone she should probably make certain that she hangs up before she calls them names and cusses on voice mail. I didn't say it in a nasty manner – I just said it like, "Hey, you should know…"
A few days later, I got a sheepish call from her. She was pretty embarrassed and said she was sorry and that she really didn't mean it all that way. She was stressed out, and hoped I understood. I said I did, which was true. We left it at that, and I've never really brought it up again, although there have been times that I make dang sure I've hung up the phone before I say anything bad!