The DNC list provides you the legal right to take action against people who call you. It doesn't block anything. Criminals will use it, but IF they can be tracked down, there is a legal basis to prosecute them. The list makes the caller's activity sanctionable. Without the list, there would be no remedy against them. On a practical basis, though, while they can be prosecuted, it doesn't do much to stop the bad spanners and fraudsters from calling and they know they can probably get away with it.
Call from 212 121 9949. I answered and there was no response. the ID was Invalid Number. This is NOT a valid USA number. Probably scam. It is not possible to block this because I do not know the calling number.
Received a call from this number, did not recognize the number but answered...... the caller said he was with some company selling some kind of medical brace equipment. "Can you hear me okay?" NO and I hung up the phone. This most likely one of the callers wanting you to answer YES so they can record your voice. BEWARE!