Once logged into your account, you can request a return online for items that have been delivered.
Go under Your Account → Ask for Return → Under the order you wish to return items from, click "Ask for Return" on the right hand side as shown below:
Once you've clicked this, select the item you wish to return and fill the required information (return/resend, quantity, reason, etc) and click "Submit":
Please note that return requests can take 1-2 business days to process. Once an agent has replied back to your request, you will receive an email notification.