I've been using this for the last 3 weeks and it works really well. It has blocked 21 spam calls up to now. After the free week they charge $30 yearly or $4 monthly.

You can set the spam calls to be answered with selected funny time-wasting recordings, but since that would be embarrassing if I get a call from a professional contact, I set them to be answered with a plain fax tone.

Now I am back to being able to pick up all calls that ring.