Call blocker might be of some help. Also don't pick up on numbers you do not recognize, or where there are caller IDs that seem odd. Or where there is no caller ID.
very annoying. when I answer to tell them not to call me there is no one on the line. I'm on a do not call list .I call back and always busy. someone do something about this please!!!!
Over 20 calls in three days. 14 one day alone. Called the number told them to never call again that I was reporting them to the FCC. Haven't had a call since.