Why bother waiting for a message? Just block the call as it comes in or just block the call, period. That's what I've been doing. I don't recognize the number, I block it. If it's a valid number then I unblock it, but lately all numbers that drop into my line are all bogus and are summarily blocked.
Calling about California Energy Program. So it is a solar scam. Blocked. The guys are using msny different unused 408 numbers. Never the same number for more than one call it seems.
called my cell phone about 8 times. Unknown caller. Didn't pick up. They didn't leave message. I tried calling back to check, it just says 'someone will return your call'. Looks like a pro setup.