If they specified a pedigree ram and got one for an agreed price, that's a contract. If they later state they don't want one with white hairs, when they've have an ample opportunity to inspect him before agreeing the deal, then that's a different contract. Whatever the reason they've changed their minds I personally would say, politely and with as much charm as I could muster, that he is pedigree and they had every opportunity to inspect him before removing him from your holding, but chose not to, which is not your fault..