Emails are necessary for delivery purposes and to identify the rightful buyer. If you cannot access the email used at Guest Checkout you may be unable to access the Product's key. In such a case, you can contact our Customer Support and provide a screenshot of the transaction details to confirm that you owned the product. If the product was not already claimed (displayed), we may be able to issue a refund, subject to the seller’s policy. 

To avoid such problems we recommend that you create an account to be able to access your inventory at all times.