No one can block a call for you. You are the only one who can stop them - 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
Telemarketer. If you call the number back you get a recorded message about removing your number so these guys have an autodialer and understand that 99.9% of the time all they are doing is irritating people. Buy a call blocker. May be among the best $50-$100 investments you can make.