I can understand why you are upset ! I would be too
If she did this then she is dishonest , unethical , and just plain wrong !
Your new baby is adorable , But even so, if you feel in your heart of hearts that you still want your original dog that you chose I would ask ( in a demanding way
) that the breeder prove the puppy you chose is the puppy you received and if it's not get your money back and go elsewhere.
BUT if you are able to let it go and are bonding with your new pup than I wouldn't worry about switching her , but I would still contact the breeder and let her know how you feel. Regardless of weather you choose to keep this pup or not , what she did was wrong.