Your buyer should not have bid as shpping was not offered to their country. If it is the teapot, it is a fragile and expensive item that you are unlikely to be able to insure for international postage.
You are not obliged to invoice the buyer and if you choose not to then you should open an unpaid item dispute 2 full days after the listing ended. Run the case for 4 full days and only close it when you see the option to say "no" to the question "did the buyer pay", this will appear sometime on day 5.
At that point you could make a second-chance offer to the underbidder but bear in mind that they are not obliged to take you up on the offer.
