Make the "deposit failed" heading red
pre-fill receiptEmailAddress in GET handler
Change the notification handler to return the list of addresses (strings) to which a notification was sent. Update the success and failure templates to display the list of addresses separated by commas if there are any.
Validate the email address entered by the user, since an invalid user-entered email address could prevent all email notifications from being sent, including error messages to the administrator. This also ensures that the user can enter at most one email address.
Don't display the error markup at the top of the form if there aren't any file errors.