Hi Pankaj,
Unless used in conjunction with some media query, that code hides any element with the classes hidden-phone and invoice, at all times. So the invoice is not visible in desktops.
I suspect the problem with the duplicate invoice visible only under certain sizes has something to do with the media queries, that don't "overlap".
Or maybe the "uk-" CSS declarations are not loaded with the modal, because the "desktop" invoice uses classes from bootstrap (hidden-phone), and the "mobile" invoice uses "uk-" UIKit classes (uk-hidden-large and uk-hidden-medium)
Roger.