For further information on who is behind this scam number, refer to this:
http://800notes.com/Phone.aspx/1-866-620-5482
It is the same people. Someone claiming to be from the Department of Welfare requesting information from you to make sure you "get your money today". They are not government affiliated. They will steal your money and you will get nothing in return. Do not give them any information about yourself whatsoever.
This could be a number used by the internet calling service SKYPE. I called my wife's cell phone from Japan using Skype (2cents/min) and this is the number that showed on the bill for the incoming call.
Got a call from this number, missed the call. Called back seconds after the call came in and got a recording that said the number I was trying to reach was no longer in service. They did not leave a message. VERY SUSPICIOUS.
They just called me back and asked for someone who doesn't live here. From researching this number, they are involved in some sort of "pay for being a winner" scam where they may ask for personal information from you -- such as checking or credit card information in order to "pay" you what you have "won. This is a scam. You should simply hang up and do not attempt to return the phone call.