Unsolicited phone call- didnt answer- no msg left

its a life insurance telemarket recording

Called and I don't have voice mail setup.

Answered, not a peep on the other end. It hung up on me after about 18 seconds.

Picked up phone but no one was there so I called the number back to get a robo telemarketer about insurance. I listened until it asked me if i wanted to know more and I said no and it said to press 9 to be added to the no call list. Which I did.