What do you mean 'confirm'?
Is there no address at all on his eBay order nor on his Paypal payment?
If they do not match, general wisdom is that the PP address is the one to use.
Foreign addresses can look strange-- almost as weird as rural Saskatchewan ones- but you should be fine if you are printing a PP shipping label.
It is also possible that the Ecuadorean buyer uses a US based freight forwarding company. This is very common and not a problem.
The seller ships to the forwarder. The item is considered delivered. The forwarder sends it ,often with other purchases from other sellers, to the customer.
You are going to lose this dispute.
The only way to win it is to provide Proof of Delivery. And you have not even shipped.
Further there is little chance that the CD would arrive at the US forwarder (or in Ecuador) fast enough to be able to prove delivery.
I hope this is the only Defect you get this year. Those things play havoc with your ability to sell.
