They call constantly. I've told them not to, but they keep doing it sometimes twice a day.

They call constantly. I've told them not to, but they keep doing it sometimes twice a day. Very annoying and disruptive.  Sometimes they call when I'm waiting for a call from a doctor or a client, and I'll miss those type of calls because of them. I'm registered with the National do not call registry but that hasn't helped with these people.