I blocked this number. It's really the only thing you can do to stop these calls. The volume of spammers/scammers far exceeds anyone's ability to stop it. It's up to us to use common sense and the tools (call blocking, don't answer if you don't know the number calling, etc.) at our disposal. The "Do Not Call List" is simply not enough of a deterrent to people who have no regard for laws or common decency!
I am sick of these bottom feeders calling me every other day, telling me my "opportunity" to lower my credit card interest rates runs out. Then they call me again and again and again. People with no return number that can be contacted should be illegal. I am sick of these pests.