pugzi,
Don't feel terrible. It's only business. You deserve to get paid for the services you provided. You are completely entitled and expected to take all reasonable actions to protect your own interests.
You could be viewed as a wimp if you did not persue your debtors with with every means available to you.
Don't make this personal. Hopefully, with a satisfactory resolution to this situation, the persons responsible will not view you in any other light than that of being a level headed businessman and pilot.