CRAP for brains. These MORONS keep calling, even when they can not get thru, because their number is blocked. They do not care if you are on the Federal and State Do Not Call Lists. Total IDIOTS!
Do not answer unknown calls and do not call them back. Consider getting a call blocking device (or app for your cell phone)-they're available online and start around $50 or so. http://800notes.com/nb/search?q=call+blockers
Also take a look at: http://www.wikihow.com/Block-a-Call