I'd need to hear what the guy has to say. He certainty should know the difference between 16 & 28. But if he made a mistake and admits he made a mistake and gives you your money back including shipping costs then he is a stand up guy. I can't imagine how someone thinks they can send you a 16 for a 28 and expect to get away with it. I hope there is a fair explanation. Let us know how it goes.