Robocall. A well done one, unfortunately, with what sounded like a kid in the background and appropriate pauses after a "Hello" and "This is Mark Morrison" so that I thought it was a real person.
Received call but didn't answer as I didn't recognize the number - no voicemail left, so probably a scam (especially based on feedback here) - blocked number
Called but did not leave a message. I called the number and it is a telemarketer. I'm so glad that I have unlimited minutes because I would be in deep trouble if I didn't.