Normally Ebay refund from your bank account if you don't have sufficient cleared funds.
Have you got a Direct Debit set up to Ebay?
That is the method they use.
if you have never set up a direct debit, they won't be able to refund your buyer.
"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)