"Call this number and learn how it works... bla, bla, bla..." It's a Robo call telemarketing scam. Recorded voice tries to make it sound like a live voice with, "Hello? Hello?," after the voicemail "leave a message" recording. The low-lifes will do anything...
Called my DNC registered landline. I answered but it was 3/13 and I don't remember if it was another get rich quick scheme.
I used *67 to call back. No ring, no sounds. Another teleterrorist.