I use this template letter. Amazon then handles it. They either refund them with their money or not. I don’t lose any money.
You are 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 requires you to wait 48 hours after contacting the seller before you are eligible to request a 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 comment in the text box.
Note: Refund requests can take a few days 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”