Damn modern technology! Has this happened to you? You call up someone and most of the time you get their recorded message ("Hi! This is xxx. Leave a message! Bye!) plus the machine message ("If you would like to leave a message press 1 or wait for the beep.). So you leave a message and that works.
However... have you ever gotten just the machine message part without the personal recorded message? I got that before, hung up, called back, got the full message so I knew it was working and left a message. She called right back. But this time, I didn't get her recorded message just the machine part and I left a message anyways. Now, I don't know if she got my message or not. So, should I call back again (and again, etc.) until I get her recorded message so I know her voicemail is working then leave a message? But what if her voicemail did work the first time? Then I'd sound pretty dumb calling again (and again, etc.). And it's already Thursday night so calling Friday would be too late for Saturday?