The easiest way to avoid phone scams is to never pick up the phone when you don't recognize the phone number of the person calling. But scammers are onto that; and they've come up with some clever ways to get you to call them. Sometimes scammers will use computer software that will call you and only let the phone ring once before they hang up. Many people call the number back to make sure they didn't miss an important call. The ring once phone scheme gets scammers off the hook by enticing victims to call them back.
Under this scenario, the fraudster didn't violate the do not call registry because you called them!
Another ploy is sending consumers a text message asking you to call them. Inc.com says there are several international area codes that appear to be U.S. numbers. If you dial them, you can run up a big phone bill.
Area code 473 is from Grenada. Calls can sometimes cost you up to $20 just for the first minute.
242 is from the Bahamas. 441 is for calls to Bermuda. Don't dial 876 for Jamaica or 345 from the Cayman Islands.
Inc.com lists several other area codes that should also raise a red flag. You can see them all here: http://www.inc.com/joseph-steinberg/do-not-return-calls-or-texts-from-these-area-codes-its-a-scam.html