Your buyer paid Ebay for the postage (Simple Delivery) so, as you did not use the label, the buyer will be refunded after a period of time. You can't get the money back that you have paid for postage.
If you have a printer, you can print your labels and then get parcels collected by Royal Mail.
You would have to deselect Evri to ensure you only used RM to send.
"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)
