For a damage claim during delivery it is the recipient who has to claim bec\ause they have the packaging etc. The only way the sender can complain is if the buyer signs over the right to make that claim, I don't know if that is possible for an overseas delivery and it doesn't sound as if the buyer would put themselves out anyway.

Have you asked for photos of the damage or a damage report? Ebay should at least let you get that before they decide in the buyer's favour however if the item is damaged and the buyer shows that then you have no choice but to refund.

The only point in having insurance in this case would be so you were covered for the full amount if the parcel went missing.