Answered (by mistake--thought it was someone I knew). Caller ID said only "wireless caller." It was a robocall telling me I won a "free cruise" but I'd have to participate in a "brief survey" before I could find out about my "free cruise." I hung up before the "brief survey" started.
I received a call from this phone number today. Did not leave a message. Thought to check it out online and found this website which provided very useful info. Now that I know they are scammers, I'll simply block them. Thanks for all of the helpful postings.