'post',
'orderby' => 'post_date',
'post_status' => 'publish',
'category_name' => 'service-system',
'order' => 'DESC',
'posts_per_page' => -1 // this will retrive all the post that is published
);
$result = new WP_Query( $args );
if ( $result-> have_posts() ) :
while ( $result->have_posts() ) : $result->the_post();?>