International Rarities Len Barber Defrauded me , by not returning coins in trade for Many Kugerrands and silver dollars Minneapolis, Minnesota

This had happened 1999-2000.  Len Barber who worked for International Rarity Group Inc.. under Harlan Rosenfeld( who is now deceased.) He now owns his own business.  He defrauded me thru the exchange of coins, giving me ones of less value after each exchange.  With the exception of the last exchange when I sent him numerous kugerrands and silver dollars and he just took them and gave me nothing in exchange. 
He started calling me after the death of my husband when I was in shock and grief.  I tried to pursue this on my own to no avail, by writing letters to various people in government and having a lawyer contact him.
 The coins involved were ll Kugerands, M. Tereasias, silver dollars,Liberties, 27 St guadens.  It would take someone of knowledge to figure out the worth as the dates are varied.