If that's Maxi in your avatar, then that's a 100% Yorkie so don't worry about that. I'm obviously in the UK so I'm not entirely sure what to do but if I lived in the States I'd be inclined to contact the American Kennel Club and the Yorkshire Terrier club (which has a great website and is very informative) and let them know that this 'registration' is being used as standard for purchasing. You could also contact whatever consumer group is in that breeder's state and let them know that she's offering puppies under essentially false pretences. Just let as many truly official groups know so then that registry can also be held accountable because it sounds like a bit of a wishy-washy and far too flexible approach to me. Good luck anyway and let me know if you need any help. He's a gorgeous puppy and you were meant to have him