All digital items have a return time period of 10 days.  If it's been longer than 10 days since you purchased the item, it's unlikely that it can be refunded.  If it's been no longer than 2 weeks, reach out to see if there are any other options.

Access Codes: regardless of if the code is redeemed, once revealed, an access code can't be returned for a refund.  If the code is received with a physical book, the saran wrap can't be removed.  If a physical code alone, the code can't be revealed.