I'm so sorry your little one lost his battle.
How sad.
It isn't your fault that the breeder sent a dog too little to travel!! (I'm with Villette in thinking that perhaps he was younger than the breeder stated).
I get so angry at breeders like that who are so uncaring toward their little ones!! Any good breeder with a conscience would treat their puppies as if they were their own children. I'd be concerned too, about receiving a second pup from her. Does she have any type of health guarantee?
I'm in full agreement and think that if there were any way to get your money back, that would be the route I would take. If not, make sure you take your new pup to the vet ASAP to have him/her fully examined.
So sorry you had to go through this. I hope that your next experience is a happier one!