Why is my Apple Music refund taking so long?

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.

Check the status of a refund for apps or content that you bought from Apple - Apple Support

It may come sooner. Banks seem to like to hold refunds as long as possible before positing to your account. I suppose they have their reasons and none of them are in your best interest. "Interest" probably being the keyword there.