No caller ID, no answer.  Simple rule.

This caller's ID is one of those generic location ones: Rutherford, NJ. Therefore, it's a scam.

Calls almost every day.  After the third call with no message on the answering machine, I blocked the number with my call blocker.  The blocker continues to log calls, suppressing the first ring as it checks the number against my block list, and hangs up before the second ring., I never hear these pests at all.