As long as your order hasn't already been roasted and/or shipped, you can cancel the order free of charge. Just head to the upper-right drop-down menu to the left of your Playlist button and select "Orders & Ratings." From there, you will see a Red 'Cancel' button on the applicable order(s). Just click that button and you're done!
*Please note that if the coffee has shipped it cannot be returned and the order cannot be cancelled (as coffee is a perishable product).