Read the info at this link, for helpful advice:
http://www.craigslist.org/about/scams
Unfortunately, it seems some folks neglect to read even the first warning:
"DEAL LOCALLY WITH FOLKS YOU CAN MEET IN PERSON—follow this one rule and avoid 99% of scam attempts."
More information about that scam (and others) is at
http://phonehelp.2truth.com/facts.html
That site also shows how other 800notes visitors have reduced the number of telephone scams and telemarketing calls they receive. (That site also has a link to Amazon's phone blocker devices and apps, as well as a page showing various government sites that accept complaints or warn about scams.)