The Verizon customer service rep suggested "just blocking the number" after expressing shock and awe that robocalls happen, and he had never heard of such a thing!
I suggest at least leaving the robocall running until it hangs up. Any given organization has to have a finite number of outgoing lines, and IVR/VRU's, so keeping them occupied should be a priority for all of us. If you've got the time to fuck around with a Real Human, do that, too. They definitely have a large, but finite, supply of call center workers. Keeping them unhappy should be a priority for all of us. The faster someone quits out of despair, the more that they have to pay to train a new worker.