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 less than 2 weeks, reach out to see if there are any other options.

eBooks: these can be returned for a refund even if opened, as long as it's within the refund period time frame.  Also, more than 20% can't be accessed.  Scrolling through the book just to review what's there can affect the possibility of a refund.