Yeah, I just don't answer. They have only called me ~once. I have Caller ID on my cell phone. If I don't recognize the number, I just don't answer. It's a minor irritant, not a crisis. I put the number into Google sometimes to see who it is for some small entertainment.
Weird automated insurance spam-sounding call. "National Insurance Alliance" or something. Said they could save $ on insurance. Completely creepy automated voice.