Ahhh, I see now, I'll test this a bit and see where the undefined issue is coming from. I might be able to piece together the npub that placed the order ased on our metrics page; will get back to you on that.
N/A is for digital listings or products that don't require shipping. Free is for listings that buyers don't have to pay shipping for, added cost for those that need to have shipping paid. Free/Pickup is if you'r fine shippibg the product and also having people picking up the product in-person.
The duplication seems like a signer issue; are they still showing up as duplicated for you after editing?
And what do you mean by the issue of listings instantly posting?