You don't show a top shot, is there any blushing on the back pattern?
Not all supers have the really washed out head but most do and it's the easiest tell-tale sign.
I have a super with tons of body blushing but with just her head, it would be hard to tell (I trust the breeder).
Personally, based on the photos, I'd say that one is a pastel.
Is he wanting to get money back? If he's happy with the deal regardless, he could make a statement that he doesn't see it as a super, ask the breeder why they think it is, ask for pictures of the entire clutch and parents (to prove the parents are what he said they were and to compare to the littermates).