Caller ID displayed as "Unknown name", following by an unrecognizable number. I let it go to my answering machine to screen the call. They didn't leave a message. I dialed back the number and encountered a robotic greeting that said, "Your call is very important to us. Please stay on the line and you'll be transferred to the next available agent." There was a moment of silence. The line rang again, then music played briefly. I then encountered a spanish recording. Rough translation: "Thank you for calling. If you would like to place yourself in the do not call list, please leave your phone number after the tone. Thank you." I didn't leave a message and hung up.