These people have been harassing me too.  They have called my work, cell, Mother and brother!  They say I have 72 hours to return the call.  They called again today and said I had 72 hours to return the call.  They told me that over 72 hours ago!  These 'bottom feeders' buy old debts for pennies on the dollar and then try to collect.  I will not give them the time of day!  Besides, what sane person would give out their address to a complete stranger over the phone!?.  If they don't already know it, they don't need it!  If the law is really looking for you, they know how to find you.  They don't need an address and they damn sure ain't gonna call you up on the phone to harass  you!  Block the number if you can!