Posts per page

Hi,

I have this wordpress code, but i have a problem with "posts_per_page" function. He dosen't limit the 2 posts per page.
Can you help me please?
Thank you for your help

<?php
$display_count = ( get_option( 'cp_sys_top_ad_count' ) ) ? intval( get_option( 'cp_sys_top_ad_count' ) ) : 2;
$term = get_term_by( 'slug', get_query_var('term'), get_query_var('taxonomy') );

$args = array(
    'post_type' => 'ad_listing',
    'post_status' => 'publish',
    'orderby' => 'rand',
    'ad_cat' => $term->slug,
    'meta_key' => 'cp_sys_top_price',
    'posts_per_page' => $display_count,
    'nopaging' => true
);

$top_query = new WP_Query($args);
?>

    <?php if ($top_query->have_posts()) : ?>


        <?php 
        while( $top_query->have_posts() ) : $top_query->the_post();
        
        $highlight = get_post_meta( $post->ID, 'cp_sys_highlight_price', true );
        $high_class = ( $highlight ) ? ' highlight_ad' : '';
        ?>

Code (markup):

 

Have you tried echoing the variable $display_count to make sure that you're actually getting a value?