Zazzle doesn’t let us see what design changes the customer made to the design, only the product choices (paper, cut, size, etc.) If it’s showing you a blank black image when you click through the link from your sales report, it likely means that the customer chose black paper - that’s what you would expect to see since Zazzle’s system only shows you the customer’s product choices, not their design customizations. I would assume that they also changed the text color to something else so it would be visible on the black paper, but for customer privacy reasons, Zazzle isn’t going to show you any changes they made to the design.