Who called from 3475589811

Picked up phone and there was silence on the other end.

This person calls every day never leaves message and will not respond when I answer

Calls and does not respond when you say hello and hangs up shortly after.

They've been calling here several times today but I haven't answered.  I wonder if this is part of the scam where they're trying to get you to say 'yes' .. some people say that instead of 'hello'.

I am on the do not call list but it does not stop calls like this or telemarketers calls even when I have a message asking them to delete me from their list. What else can you do to get them to stop calling?