As of version from September 2011:Under 11. Cancellations and Refunds:"You agree to the electronic delivery of Content being initiated concurrently with the placement of your Order. You will not be able to cancel your Order once it has been processed. The nature of the Content is such that it cannot be returned."
You can't get refunds or cancel transactions, because they are immediate, unless any of these happen:"In the event that after your Order you discover and promptly inform Nokia within 48 hours that (a) the Content you have ordered is faulty; (b) the Content Nokia delivers to you does not match the description of the Content you ordered via the Service; or (c) technical problems delayed or prevented delivery of your Content or accidental multiple orders caused by such technical problems, your sole and exclusive remedy with respect to such Content will be either replacement of such Content, or refund of the price paid for such Content, as determined solely by Nokia. Otherwise, no refunds are available. If you encounter any of the above issues, please contact Nokia Customer Support."