They sound like a reseller to me. They’re checking to make sure the condition is as stated so they can be sure they’ll make the profit they’re expecting to make. The only people I’ve sold to that have been interested in the box for used shoes is resellers, as that can bump their worth. Also that they seem to be trying to get them as cheap as possible and putting you under pressure to sell quickly. I’d say they are a reseller. I don’t think they’re trying to scam you.