reimbursement for shipping of item

[cocowool]

Who contacts USPS when an item seller mails and arrives damaged to buyer

[martin2001]

You should ask directly whether you are asking as a buyer or as a seller. If the former, you need to file a case, Item not as described, with ebay and follow the steps. That's all you need to do to get your money back. If you are a seller, most USPS services include insurance (e.g. packages mailed via Ground Advantage are insured up to $100), so you would have to file a claim with the USPS.

[simba6]

The seller does.  The buyer is covered by the eBay money back policy.  They just have to click return this item and select arrived damaged.  The seller has to refund in full and they deal with the shipper.

[kensgiftshop]

If you're the seller, you refund the buyer, then you file a claim with the carrier.