Yes, I agree with Celeste. He should have repaid the loan, as verbally agreed on the phone, and then talked to the bo for payment or partial payment.
All I will say is that when someone shows/demonstrates that they are not trustworthy or honorable, take them at their word. He did this in how he treated his horses and how he conducted himself. Sadly, the OP is out of the cash, but way ahead in the good Karma department.
Be the kind of woman that when your feet hit the floor each morning the devil says, "Oh crap, she's up!".