I have received a few of these messages from them. They are more likely to be trying to fool people into letting them in to your house for potential robbery, after they survey your LACK of security!

Did not leave message.

Answered and said "hello", twice. No response. I hung up and called the number back and got a line in use set of beeps.

Did not answer and it left no message.
   If you dont recognize the name/number, DO NOT ANSWER. If you happen to answer, DO NOT RESPOND IN ANY WAY; NOT BY VOICE, SELECTED NUMBER OR CALL BACK! After all, they are scammers and you dont really know what you answered or consented to do, give or buy, for which your number may be billed.
    Scamming and phishing only works if there is a market (target, sucker). They are bottom feeders that have no limits, conscience,  mothers, or legislation  (DNC) except you.
   Legitimate caller will be identified, will leave a name, message, and call back number, giving you the option to respond.
   I wish all the TV stations would run programs at prime times on scams and cautions; how to report and deal with them. That would be public service in public interest, and hopefully, make these scammers into real losers.

I got that "security system" call from Arvin CA ... told them I have 3 'security' rottweillers ... and a freezer full of meat --> from the last 3 intruders.