Is this normal?

On March 13 2025 we shipped a nice D&D book to a customer in a nearby city. The total order was just under our threshhold for signature confirmation.

March 15- USPS says it was delivered to Mailbox

March 17-The customer reached out to say that he couldn't find it. We responded with the usual, 'please check with neighbors, housemates etc.' and confirmed that the address was correct.

March 20-Customer initiated an A-Z claim.

March 21 at 3:06 AM-From Amazon, "We have granted an A-to-z Guarantee claim of $91.94 on the order 111-4386708-7841007. We have debited the amount from your account but have not counted the claim against your order defect rate"

March 21 6:55 PM-From the customer:

"Thanks. It was actually delivered today. I went to the post office yesterday and they were confused and couldn’t give me an answer, so I was surprised when it arrived almost a week after it said it was delivered. Who knows but it’s in great condition, thanks for responding!"

March 28- I appealed the A-Z claim by quoting the customer's message and references the message history. A few hours later we recieved a denial of the appeal:

"Thank you for taking the time to provide us with more information regarding your claim on order 111-XXXXX-7841007. Upon further review, we have decided to uphold our original decision...We have reviewed all available information and determined you have not provided sufficient evidence to prove delivery. [emphasis mine]

While we're not happy to eat the nearly hundred bucks, I suppose its just a cost of doing business. However, we're leaning towards quitting Amazon altogether and if this is how they are now doing stuff, it pushes us towards that decision. Especially, as USPS's service is likely going to degrade in the near future.

Thoughts?