I've gotton these too.  Must be how they think they can get around the no call list.  Told them to take me off their calling list, and they called back 3 more times right away. The last time I played the game with him, when he asked me where my pain was located I said "Up your A**"  and then hung up, and they haven't called back!

called back and get music

I answered to see what they were trying to sell and hit the 1 to get an agent.  Not only is the initial call a robo, but the AGENT is a robot too.  If you give a nonsense answer, or something that doesn't fall into their scripted answers, and they hang up.  Then I blocked them on my Panasonic phone.

Hangup call

call answered by my machine.  No message, just a hang up.  Caller ID set to the phone number/  I've seen this one often enough that I've memorized the number just from seeing it so much.