I've started answering unknown numbers with, "Hola!" and then when they start their spiel, I just keep saying, "que, que?" It's a fun way to spend an afternoon.
The number appeared with "not in use" answered anyway an waited. A male voice eventually came on apologizing for computer call and asking if I would donate to homeless veterans by way of them sending me an envelope (usual scam). I told the scammer that this spoofed number was one of many used and informed him that this was recorded