hung up when answered?

Been getting calls from this number for weeks now; if I don't recognize the number, I don't answer, yet a message is never left on my VM. I tried calling the number back to get an idea of who it was calling, and I get a recorded message saying, "Thank you for calling. Please stay on the line for the next available representative." Then the call gets disconnected.

I have been receiving calls from this number for over a week and at different times of the day. I don't answer numbers I don't recognize, i figure if its important they will leave a message. No message is ever left and I haven't tried to call it back either.