I believe I just received a robo-call that tried to mimic a real human being. Pleasant and cheerful human being. It greeted, responded to a greeting from me, then started the conversation offering their services. It stopped when I spoke, OK'ed, then continued to ask the same question again in the same tone of voice. The question assumed a yes or no answer. When instead of the answer I said "I am not interested in that service" it just went silent, as if not knowing what to do next. The call did not disconnect. I imagine it started to flash some red light for a human to pick up the phone and intervene.
If it was a human -- it was the most bizarre sounding and inefficient sales person ever.
If it was a robot -- I am impressed, but horrified for what the future holds.
It actually makes sense if you think about it... Cold calls are heavily scripted. Half the time even humans making them sound like mindless drones. Why not replace them with Cortanas and Siris of the world?