I get the one-rings, the no-messages, the unknown names/numbers, the "toll free" numbers, and now, unfortunately, just to make it really tricky -- "local area code" ones.
The same spammers will go on leaving repeat messages FOR YEARS, and they have no end of numbers to show on your display. I've learned to recognize a lot of them, and a lot of other suspicious ones that turn out to be more of the same.
If I don't immediately know the number, NOTHING gets answered. Period. You can be on all the Do Not Call lists in the world (and I am), but no one's looking out for you. Just completely ignore these jerks. Now and forever.