Seller Fulfilled Prime - Customer Returns

You can file a SAFE-T claim for the value of the return postage label.
Just remember that you cannot claim for the value of the return itself since the customer is entitled to return an item for any reason, just not with a pre-paid label.
Unless of course there is a separate reason for wanting to claim back the refund value, such the item arriving back with you damaged, etc.

It is usually best to collect evidence of the item being correct/undamaged/etc. as soon as it arrives as this will help with the SAFE-T claim.