I didn't get the detailed of why they have rejected. As a matter of a fact, when my fiance asked him please give me a reason why you are rejecting, he said, sorry I can't give you the reason. Go ahead and reapply for a different category. However, I spoke to the lawyer and she said, the best course of action here is to get married and reapply. I will suggest the same to you. Most likely you will never hear back from USCIS.