I had a similar situation recently. I got two babies in from the same breeder who refused to eat from day one. They were monitored closely and aside from not eating acted fine and looked normal. One day I checked on them and the smaller of the two had passed away. No necrospy was done at that point but I had been talking with the breeder back and forth throughout the not eating. I know people believe ball pythons are picky eaters but for a young snake not to eat is not good. At first he came off defensive as if I was placing blame on him but I let him know that there was no way to confirm why the first snake had passed away. Days later the 2nd snake started showing severe signs of RI and was taken to the vet immediately. It was cultured and confirmed and the vet started her on Antibiotics. I'm sure my husbandry wasn't the cause of the RI because my racks and conditions are spot on. The snakes were sent to me sickly but time had passed and I didn't want to blow the situation out of proportion. To be honest though a breeder should at least care what is happening with animals they have sold to people. There are no rules on the subject but I can tell you I will never purchase an animal from the person who sold me those babies.
The baby has been responding well to the injections and has not shown and severe signs in a few days and hopefully will start eating soon.