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 $45. http://800notes.com/nb/search?q=call+blockers
I received a machine call which claimed to be from its and scared me alot.I called the no back to tell me am peeing 4567 sold and it's a criminal offence to evade tax,so if I wanna settle out of court I should go to wall mart,buy a greendot whatever card and give them the info so they can stop the legal case on my name...This is absolute scam and am surprised this is happening in the US.