1. Log in to your Seller Central Account.

2. Click on the "Payments" tab at the left part of the page. Select "Payments".

3. Once you've landed on the Payments page, click on the Transaction View Tab.

4. Once you're on this page click the drop-down tab labeled "Transaction Type" then select "Refund."
5. Choose a date ranges (Statement Period, Past number of days or Custom date range) and then click on the "Update" button.
6. Proceed to download your report by clicking the "Download" button.
7. After you click download, Amazon will generate a text file for you to work with. Simply copy and paste everything in the text file into an Excel sheet to read the report. Here you will be able to sort your information even further, allowing you to find exactly the information you're looking for.

8. Copy and Paste into Excel.
9. From here you can easily format the table as needed. You can sort by refund amount, the order's date, the order number, and any other column in the table.
Using this exact method there are a number of other reports that you can generate using this tool. Other reports available here include:
• Adhoc Disbursements • Order Payment • Refund • Chargeback Refund • Liquidations • Liquidations Adjustments • A-to-Z Guarantee Refund • Service Fees • Shipping services purchased through Amazon • Paid to Amazon • Previous statement's unavailable balance
Check out the following article on the MyAmazonGuy blog: https://myamazonguy.com/how-to-find-a-refund-report-on-amazon-seller-central/
For more information and a visual walkthrough of generating this report please see the following video from Steven: https://youtu.be/so3wJMrV2Ek