you are very fortunate that when you called back you didn't get a 1500. phone bill (or worse) overseas. my advice is do not call back for a couple of reasons. 1. now they know they have a person 2. now they have whatever info you gave them 3. you don't know who they are or what they want. if it is that important they will send a letter
Actually they are guilty of numerous counts of Harassment by Communications if anybody has the time you can document their unwanted phone calls whether you pick up the phone or not and can get a nice settelment if you bring them to court. You should report the calls to the proper government Agency. They are not looking for anybody they tell you as they are looking for anybody they can con into sending them any money. If you ever get the urge to send them money then, flush the money down the toilet instead. Social Security numbers are for Social Security purposes and should not be given out especially to the halfwits calling and harassing people on the phone. This is a good site.