I am so sorry for your loss. Just 13 days, I can't even imagine.
I know your question was about what to do about the breeder. My only thought is that, did you happen to have a contract with the breeder? That said if there was a health issue she would replace?
I am so sorry to say this, but I have a feeling that if there was not a diagnosis, you may not be covered. The breeder could come back and say he choked or got into something.
Once again I am truly sorry for you loss.
