We have asked the post office before - they said that once it has left the country, any return to sender action will cost at least what was paid to send it. If the destination country is a place like the US that stopped their economy service to cut costs, then the return would be by air, which is even more costly. In a situation where we have processed an order against our published timelines, we can only pursue something like that as a zero-sum exercise, which means the cost of the shipping and the return shipping would come out of the refund.