A reputable breeder should offer return of your money or an exchange, but it depends on if you have a contract and what it says. The very best breeders offer your money back and let you keep the dog, but the majority want the dog returned and then, of course, your too attached to do that so it's not fair. It would be covered under congenital defects in a contract. If you don't have a contract, there are states that have lemon laws on dogs that you could probably go to Court and get some results. Here's a link to a thread that Yorkiekisses posted on the states and their laws regarding the sell of puppies:
http://www.yorkietalk.com/forums/sho...ght=lemon+laws