As soon as you pay for the item, the seller receives an email and the sale appears in 'orders' telling the seller it has been paid for and to send it.
As advised, for this one, you need to blame the seller, not Ebay.
"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)