There is no such thing on eBay as "lost in the mail".
There is an "Item Not Received".
You are responsible for secure delivery to the customer.
But you can respond with the Proof of Delivery /tracking number and win the case.
If you cannot show the item was delivered, you must refund promptly.
If the item shows delivered but the customer claims they did not get it (porch pirates, etc) that's the customer's problem not yours.
It is the buyer's responsibility to have a secure spot for carriers to leave packages.
https://www.ebay.com/help/policies/ebay-money-back-guarantee-policy/ebay-money-back-guarantee-policy...
Returns are a different question.
We can have a No Returns policy, but we cannot have a No Refunds policy.
Even with a No Returns policy, the seller has the right to demand the return of the unwanted product before refunding, although they will probably be paying for return shipping.
No refund without return is a sensible policy.
And sellers can also opt to abandon the purchase and refund without return (Glass sellers don't want a box of shards returned.)
It is the general opinion on the Boards, that a No Returns policy leads to more refund claims than a friendly Returns Accepted policy. And that the returned goods are more likely to be in good shape and saleable when they are returned.
The Service Metrics is not the same as getting a defect on your Seller Dashboard. It is a completely separate way for Ebay to evaluate it's sellers. For INADs/SNADs, the mere fact that the request was opened makes it count against the seller in the Service Metrics. Even if the buyer made a mistake in opening the request. If it gets opened for any reason, it will count against the seller.
However, sellers will not be subject to evaluation that the Service Metrics provides until they have at least 10 INADs or SNADs.
Buyer's Remorse claims don't count. And INRs are counted differently.
