I have come to believe that wasting the robocaller's resources are the most valuable option. To that goal, I keep the phone listening to the entire recorded spiel. This is worthwhile sometimes. At least twice, I've gotten a call from "Barbara" in a distinctly male voice. Hilarity abounds! If you don't at least listen to the recording, you're pawning the problem off on someone else. After that, I always press 1 or 9 or whatever to get to a human operator. I try to consume as much of the human operator's time as possible. I ask them to repeat things, I hem and haw while answering. I actually have an expired gift Visa card in my wallet to give out as a "valid" credit card number. I will also note that you can transpose any two odd-position or even-position digits except the last digit (which is a checksum) and the first 6 (Issuing Institution Number). That should yield a wrong credit card number that passes the checksum and IIN lookups.
I have had a full bladder when I've received a call from "Rachel" or "Ann" a couple of times. I've taken this as a sign to let the human operator listen to the cheerful tinkle of urination, and the gloomy finality of a flush.
I believe that the robocallers and the human operators are from different organizations/crime families. If you listen to the robocall all the way through, you've consumed resources of one pack of assholes. I imagine the robocallers get paid on the handoff to the boiler room full of dickweed "operators"/fraudsters. So you should probably try to get through to a human, and then waste their time, as that is time they're not spending defrauding someone a bit simpler or more trusting.
In conclusion: Cardholder Services delenda est!