To give another deviant a direct link to this FAQ answer, use the following code in your comment or forum post:
Is there a time limit regarding reporting unsatisfactory orders?
For Premium Subscriptions:
If you have made an error while purchasing a subscription, such as subscribing the wrong user or putting your order through twice by mistake, and would like a refund, your request must be submitted to us within 48 hours of your purchase. Requests made after this time frame will be denied.
deviantART will not refund the fee if your account is banned for misconduct on the website or for any other administrative action taken on your account because of a violation of our publicly stated etiquette and submission policies.
For Prints, products and other Print account related items:
Refunds:If you are unsatisfied with the quality of your order because it arrives damaged or defective, you may request a reprint. The time frame for requesting a replacement is within within 7 days of delivery. Please submit a Prints Customer Service Ticket and consult with a Customer Service Representative for more information regarding your situation.
If you use a standard credit card a hold will be placed by your bank on your account in the amount of the purchase at the time of your order and will remain on your account for up to 5 business days. The funds will not be taken from your account until your purchase is shipped.
Please note that PayPal does not support pre-authorization and post-authorization services for holds, and your Paypal account will be charged upon submission of your order if you choose to use this service. If using PayPal to purchase items with an eCheck (electronic check), the order will not begin processing for up to 14 days from the order's placement while the check clears.
Order Returns:If you have a problem and wish to return your order, please submit a Prints Customer Service Ticket and consult with a Customer Service Representative for more information regarding your situation.