Go on Amazon and for $30-40 and order a call blocking machine. Do not call list is worthless. They are probably using the do not call list to make calls.
The blocker is about the size of a deck of cards. When they call, pick up your phone and, push the button on the blocker. Or you can block the number by entering it later on. Have to read directions. We got the one called (call blocker). Worth the money.