Computer scam - they will not respect your request to put you on their Do Not Call list, and they are persistent and unscrupulous. Best way to handle them? Act interested for a second or two, then tell them, "Hold on a sec," and then go back to whatever you were doing until they eventually hang up. The more of THEIR time you waste, the fewer calls they'll be able to make and the more likely they will voluntarily mark you as a Do Not Call.