The seller does not have to file the damage claims IF the seller waves his rights to the claim over to the buyer. All this takes is a signed document stating that the seller was transporting the buyer's property to them and that the item belongs to the buyer. The buyer is then free to file and collect on the claim and do with the damaged items as they see fit.
If one is adept at dealing with shipping companies, this may be the best route to go. If you are not adept at dealing shipping companies and insurance claims, the buyer is better off having the seller refund their money and letting them deal with the claim. If the seller has a selling clause like that mentioned above, the buyer shouldn't expect any form of refund, retribution or help in resolving the claim, so long as the item was properly packed and fairly represented to begin with.
If the shipper accepted the item for shipment and accepted funds for insuring the item, they can't legally refuse the claim so long as there is visible physical damage to the carton used to ship the item. This may end up in taking them to court, but once they accept the package into their possession and receive payment for insurance, they've acknowledged that the item met their shipping standards and that it was their responsibility to transport it safely.
This is a pretty cut and dried business transaction and one has to treat it as such. Shippers always try to make this a very complex procedure as the more complex it is, the less likely it is to get resolved. No resolution means no pay-out on their part, and that's their whole goal. Sean