Why haven't I received a refund that says it has been refunded?

How long has it been? It can take a while after a refund has been approved. See the following from Check the status of a refund for apps or content that you bought from Apple - Apple Support

When will I get the money back?

If your refund is approved, the funds are applied to the same payment method that you used to buy the item. Here's how long it takes for a refund to appear on your account or statement:

Store credit—It might take up to 48 hours to see the refund in your Apple Account balance.

Mobile phone billing—It might take up to 60 days for the statement to show the refund. Processing time might be affected by your carrier. You can contact your carrier for an update.

Credit and debit cards, Apple Pay, Apple Cash, and all other payment methods—It might take up to 30 days for the statement to show the refund. If you don't see the refund after 30 days, contact your financial institution.

This is primarily a user-to-user support forum; other Apple users like you.

See my previous post for the maximum times. If it is to a debit or credit card it may be up to 30 days. If you don't see the refund after 30 days, contact your financial institution.