Why does the buyer want to return it? You only need to cover the return postage if the item was not as you described. If the buyer has not opened a case DO NOT REFUND!
Please DO NOT refund until you have the item back in the same condition it was sent.
Some buyers send back a completely different or broken item instead, so always wait.
You first need to send a shipping label - but only if there is an open case.
Once you have it back, then you can refund.