I am so sorry your little one is ill, you probably thought paying more meant better dog.
It just breaks my heart that these breeders can be so unethical and fool the public every day as they do.
My first and second dogs were from a pet shop and I was lucky, they both were fine. My third was purchased much later in my life and she was a champion from a well know breeder and I paid less than the pet shop costs. I did get to know her but that doesn't really mean the person is honest. It's a pain that we have to not trust however when one has that sweet little Yorkie face looking at you, it just melts our hearts and these breeders know it only too well.
Do keep us informed and I'll be praying for her.
(((hugs))) to you.
Joan