I think you absolutely deserve to be refunded some of your money, Buckshot. Unfortunately, from what I've heard about this guy, I doubt he will give you a cent.
I am not sure the deal with airlines, but I think it would be very easy for someone to say that a 4 week old Fila puppy is 8-12 weeks. I remember your first photo of Buckshot and he didn't look like a 4 week old puppy. I'm not sure what kind of paperwork airlines require, but I wouldn't put it past the breeder to have lied about that too. Perhaps he had two litters at once and swapped records - who knows.
If the dog was purchased from an ethical breeder, you most likely would be refunded part of the purchase price (as you did pay for a breeding quality male) but then again, if he was purchased from an ethical breeder you would not have recieved him sickly and at 4 weeks of age.
I think the best thing you could do at this point is neuter Buckshot (for health reasons more than anything else - undescended testicles are at a higher risk for cancer) and consider this a learning experience. I'm sorry you got decieved like that. My dog's breeder did her best to rip me off, too. (I'm sure she feels really good about herself knowing that she cheated an eager, ignorant 13 year old out of her money
)