If it was sent using Ebay Simple Delivery, it would have MARKETPLACE SELLER on the label and Ebay would have refunded you, not the seller.
If it was sent by any other method or you bought from a business seller, the seller would have refunded you.
If that was the case, you could contact the seller and offer to pay again.
"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)