A call center unfamiliar with the complexities of voice mail. They seem startled that no one is there when it answers. My intro message is purposefully brief so their software thinks it was answered by a human and includes key words that cause it to connect to one of their drones. Many robo dialed calls key on "hello" or other greetings. Try it, as it is kind of fun to have them talking to air. Perhaps if the cost of calling goes up there will be fewer calls.