Problem is, the card itself could be legit but the "method" that was used to obtain them might not be. That means Amazon could still shut it down in 1 day or in 4 weeks and do a chargeback.  No one knows that and only has your "word."  For that reason your asking price is way to high for the risk and the fact you don't seem to accept escrow and buyer must pay first.  Those are always large bright red flags.  Buying small to gain trust then getting screwed on a large purchase is a major scam that happens around here.

Not saying that is what you are doing but it does happen and that's why most people are skeptical.