Business sellers have to pay listing fees and sellers' fees. They have to buy stock, make a living wage and possibly pay staff.
They are legally obliged to allow buyers to return their purchases for any reason.
If you are just getting rid of unwanted items, you could feasibly reduce your prices to cover the BPF - remember, until October 2024, private sellers were paying about 13% (+30P) on the selling price and postage cost.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)