The do-not-call list works to some extent, but not as many people want it to work.  
It does NOT prevent scammers and spammers and hackers from calling you.
It DOES give the legal system a way to prosecute and fine them once they are caught.
It's hard to catch them.
They don't bother getting the list of who's on the do-not-call list.
They call you anyway.  
Your best bet is to not answer if you have caller ID and there is no ID or it's not someone you know.
If you have a recorder or answering service, if an unknown caller has valid reason to call you, they WILL leave a message.

Sorry to tell you all that the "Do not call" list no longer works. This new administration has given telemarketers the go ahead to make these calls and is attempting to pass it off as "Job creation". They said that allowing telemarketing calls will open more jobs in the field. Idiots. There is no such thing as privacy anymore. We even tried PAYING to unlist our number and they call us anyway via random call generator.
We need a system where we can block calls from these people. No I don't have an I-Phone so I don't have this option and my landline is even worse.

It has nothing to do with the administration. The technology is making it impossible to stop scam artists.

You're right about the administration but wrong about the technology. Telcos could stop this almost immediately, but their profits are making it impossible to stop.

Be careful doing this as there's a new scam where they'll call you, let it ring once and then hang up.  When you call back it routes the call to an international number and they charge your phone at least $19.95 for the call you made.