Ebay offer you these choices:
Accept the return and provide a label
Refund the buyer
Message the buyer.
You can't refuse the return.
If you don't provide a return label and accept the return, after 3 days, the buyer can ask Ebay to step in.
Then, Ebay will either provide a label and charge you for it, or refund the buyer from your funds and tell them to keep the item.
Take the advice from Ebay and accept the return.
"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)