It isn't hard. Your home loan is public record (at least in my state it is). All those documents you sign get sent and recorded in the state and are easy to look up. Once you know who the person is, where their property is located, and who they owe the money to it is a simple matter to call and talk to the right people. Typically people who are owed money aren't that picky on who is paying them back. Trump with his fame and army of lawyers would have little trouble doing something like this.