I don't quite understand...the contract you signed is not the same as the one you uploaded? Or the same wording just this isn't the signed copy?
This contract doesn't even mention the parents, hence you haven't even parentage of this kitten...you may well have paid $2,500 for a mixed breed kitten with some Savannah and some other breeds mixed in. We did see one kitten represented as that ridiculous "F2.5 Savannah" turn out to be an F3 Chausie and the closest the Savannah was was 6 generations away. Hard to tell from that contract what you actually got.
Coccidia is a difficult infection, there's no easy test for it. It's usually diagnosed by visualizing down a microscope a fecal float. This requires enough infection for coccidia to be shed, so up until the infection breaks a kitten will not show any signs. Some cats can carry coccidia without symptom, but stress (for example the stress of cargo shipping) can tip the balance and the coccidia overgrow and cause infection. I do hope that your vet is not treating this with an old-school type of medication like Albon (Sulfadimethoxine) but suggested Ponazuril or Toltrazuril which are newer and far more effective at eradicating the infection.
Although I do think that you were "screwed" in the sense that you have paid too much money for an unregistered mixed breed kitten, I do not believe that the contract you signed promises you anything that you could go after them for. If you had demanded you wished to return the cat within that 48 hours (and not sure how soon after her arrival "a week ago" was), then I guess you could demand that they take her back and refund your money. This contract doesn't make false promises about what the kitten is...
Like Patti, I would be concerned about your location and hope that you do keep your kitten safe.
