You can find additional information on Purchases and Sales Policy in sections 5 and 6 of the Terms of Service.
 

Digital Downloads
For any Digital Download that is purchased and digitally downloaded from the Daybreak Websites, refunds will be permitted until the earlier of (a) 14 days after purchase, and (b) 24 hours after you first log into the applicable game following the purchase.

Membership and Game Subscriptions
Membership purchases are non-refundable. Most memberships are also recurring, and will continue to bill until cancelled. If you believe that you were billed after your account was cancelled, then you will need to provide the date of cancellation as well as either the cancellation email or reference number (if you cancelled through Customer Support) of your cancellation.

Steam Purchases
All purchases through Steam are subject to their return policy. You can find more about the Steam Refund Policy here: https://help.steampowered.com/en/faqs/view/784C-923B-A4A1-C825

Virtual Currency
Virtual Currency (Daybreak Cash, Marketplace Cash, Battle Cash, etc.) is non-refundable and non-transferable. Virtual Currency cannot be moved from one account to another if it has been purchased on the wrong account. Always ensure that you are logged into the correct account before making any purchases.

Virtual Items
Virtual items are digital objects such as armor, weapons, pets, potions, etc. These items, whether purchased through the Marketplace with real or virtual currency or through game play are non-refundable. Support cannot swap out items that were purchased by mistake for other items, nor can they change the payment type on previously purchased items.

Double Purchases/Purchase Failures
If you received an error when purchasing your item and now see more than 1 charge on your statement, you are probably only seeing an authorization. These will typically drop off after 48-72 hours.