No one has been named here - so I don't see how this can be defamation of character in any way.
Also, from what's been described, this person doesn't have any claims here, imho. You offered several options to this buyer, she took none. She then bred a dog who she claimed had an observable and vet-documented health defect. That action says it all, I think.
__________________ ~ A friend told me I was delusional. I nearly fell off my unicorn. ~ °¨¨¨°ºOº°¨¨¨° Ann | Pfeiffer | Marcel Verdel Purcell | Wylie | Artie °¨¨¨°ºOº°¨¨¨° |