I don't know where you live but here in California there is a "Puppy Lemon Law" this can be used for other animals, for consumer protection. I would also contact all animal abuse agency's and report her as a reckless and abusive breeder. That should make her uncomfortable. I would contact her and inform her of your proceedings and that you are tried of this runaround, that you have tried in good faith to resolve this issue to avail. hopefully this should get her to be more cooperative.I'm starting to think there was no vet visit .
Most folks just drop it ...and breeders know this, (you be the one to make them accountable)