If you get one of these calls, don't answer it and then call it back.. you've just defeated the purpose of not answering in the first place. The minute you dialed and the automatic recording picked up and answered, your number was recorded as being a live active number regardless if you blocked it when you dialed.. the electric impulse recorded it just as it would have if you had picked up when they called.
Two calls over two days. One was answered and the caller hung up. Second one was not answered, but no message was left. Calling back with my ID blocked got me a recorded message offering the opportunity to press 1 and be placed on a do not call list.
Recieved a call from the number today, let it go to VM, none left. Called back it rang twice and automated recording said it was an "non-working number".