Pre-orders aren't paid for until they are released and you download them, so there shouldn't be anything to refund - if any tracks on the album were released early and you downloaded them then they will remain as purchased tracks.
About pre-orders : http://support.apple.com/kb/HT5714
When the pre-order item becomes available, your account will be billed for the pre-order, and the item will appear in the Purchased section of your account.
Some pre-orders include songs that are available for download immediately. When you pre-order, you will be charged only for these songs and you will receive them immediately.