This exact issue was an issue for me and I asked already a Posek as this is part of my income.
Instead of trolling during the Asseres Yemei Teshuva , why didnt you ask a Rav yourself. He would have told you a Halachic Sale is where Money is exchanged and a Buyer received an item (Sorry if I forgot the exact Hebrew words).
In an online sale the buyer did pay for the item, but he did not recive the Item.