Returns are not currently supported through the Global Shipping Program.
However, a return can often be arranged directly between the buyer and
seller. The buyer should review the seller's return policy, and then
contact the seller for next steps.
If there's an open cancellation request, return request, eBay Money Back
Guarantee case, a report that an item hasn't arrived, or an open dispute
made outside of eBay against an order, then the Send refund option will
not be available.