WOW! Congratulations! I'm so happy you got the job that you wanted...and here we were bashing them! Oops! All that matters is that you are happy!
I would definitely pursue some type of action against the former vet for the bad reference though. I'm pretty sure it's illegal, I just don't know about your state.? I can check the internet on Monday for you. (Right now I'm on my ancient computer at home and if I open another window, I'll probably lose the whole system!)

Anyway, so glad to hear you got the job. You deserve it!