Don't know who this is, but it's definitely a robo call.  My call blocker connects with the caller and informs them that they must press a key to continue the call.  A live person would do that and the phone would ring.  A robot on the other hand wouldn't know how to respond to a request like that and would just sit there waiting for the call to go through until my call blocker disconnects them.  Since my phone didn't ring with this call, it's more than likely a robo call or maybe just someone who didn't feel going through those motions.