Details of finding the purchase are here:
Finding your order details
To start a return request or report a problem with an item you bought as a guest, you'll need your order confirmation email. This is the email we sent at the time of your purchase with all your order details. The subject line starts with "Order Confirmed".
If you can't find your guest order confirmation email, select the button below and we'll send you a link to your order details.
Find guest order details
However, if the item is shown as delivered and the tracking confirms this, Ebay will not expect the seller to refund. There is no need to phone Ebay.
Unfortunately, doorstep theft is increasingly common. The payment provider may be able to help.
"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)