CID showed Unknown, so I let the answering machine take it. They didn't actually leave a message, but stayed on the line, so the machine recorded boilerroom/call center back ground noise. Scammers.
Goofed on the guy and played along -- until I got bored.
Then just put the phone by the speaker as it was playing a song from Disturbed.
Hung up a minute later.
This caller has called us more than once. They simply hang up which I assume means they are preparing to put us on some call list. This is not a legitimate business. Please investigate.