Early this year I often received a voice message like this:
"This is a confidential and important message for ... I am calling from MCO Financial Systems Inc., a debt collection company... "
At the beginning, I just ignored the message. But I received the message too many times, so I called them with the 800- number they provided. I just told them: "My phone number is on government's Do-Not-Call list, please do not call this number again." I further told them to remove my phone number from their calling list. From then on I never received calls from MCO.