I wouldn’t write it off as spam just yet. Sounds like they didn’t give you a lot of information, but they could be asking if you are willing to be a drop ship vendor for them. For instance I sell a selection of my lace bowls on another ecommerce site. I drop ship, meaning customers by my bowls from their website, but I package and ship them to the customer. It’s been a great relationship so far. Might be worth looking into if that’s what they are referring to.