That's really weird.
I got that call too, and no answer, even when I called back. I tried *67 too.
The weird thing is that I get multiple "hang-up" calls with the number. This is not the only number.
This number called me twice and hang up without saying anything. I called back and it was answering machine saying that it is NON-WORKING number at UM. PLs hang up. very wired.
This is an outgoing number from University of Miami. It seems from the posts above that any number of sub-organizations from UM can be calling you from the number, as it seems to be some sort of VOIP or extension system. The organization that called me was one of their health departments in response to a study I voluntarily signed up for. I did not pick up. The caller left a message.