Financial questions that need an answer

I was home sick two days last week and somebody kept calling during the day when most people are at work. There were more than 30 calls apiece day from 800 numbers. We don’t answer calls from numbers we don’t recognize, but they never leave a message. They never call our cell phones, and they don’t call at night or on weekends when somebody is usually at home, or at least no where near as much. It was so frustrating that I eventually turned the ringer off. We don’t know who it was, because if we try to call back there’s a recording saying “please hold” and you’re place on hold for forever, the number doesn’t take incoming calls, or they want to know who we are but won’t refer themselves. Now I started looking at the caller ID when I get home and these people are still calling all day long. We’re on the “Do not call” list … what else can we do to stop this madness?