Piggybacking off what @Seller_LTNvvFJ2jqJOv and others have said, below is a script template I copied off someone else in the forum years ago (thank you stranger). I send this to people upset about missing packages or stranded packages:

Hi [customer]

Please follow these steps to receive a full refund:

You may be eligible to request a refund under the A-to-z Guarantee if “You have not received your package and three days have passed since the maximum estimated delivery date or the tracking shows a delivery confirmation, whichever is sooner. Note: Amazon also require you to wait 48 hours after contacting the seller before you are eligible to request a refund.”

Requesting an A-to-z Guarantee Refund

To request a refund on an eligible order:

Go to Your Orders .

Locate your order in the list and click Problem with order.

Select “Package didn’t arrive” from the list.

Select Request refund.

Enter your comments in the text box.

Select Submit

Note: Refund requests can take up to one week to investigate. Amazon will notify you of their decision via the email address associated with your account. To view the status of your request, locate your order in the list on the Your Orders page and select Problem with order.

To receive the maximum refund allowed you need to select “Package didn’t arrive”

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It's a bit wordy so you can chop it up some, but it gets the point across.