What am i missing out in this theme_mod

I create a customizer to select specific category post but my challenge now is that if i click selected category, the loop is not displaying it rather still display all. What am i missing out in this code

	<?php
// Get pages set in the customizer (if any)
$pages = array();
for ( $count = 1; $count <= 5; $count++ ) {
	$mod = get_theme_mod( 'showcase-page-' . $count );
	if ( 'page-none-selected' != $mod ) {
		$pages[] = $mod;
	}
}

$args = array(
	'posts_per_page' => 5,
	'post_type' => 'post',
	'post__in' => $pages,
	'orderby' => 'post__in'
);

$q = new WP_Query( $args );
$leadingcount = 3; 
	?>
		
		<div class="row">
			<?php while ( $q->have_posts() ) : $q->the_post(); ?>
				<div class="col-<?php echo $leadingcount; ?>">
					<h3>
						<a href="<?php the_permalink(); ?>">
								<h2><?php the_title(); ?></h2>
						</a>
					</h3>
					<?php the_excerpt(); ?>
					<?php the_category(); ?>
				</div>
			<?php endwhile; ?>
			<?php wp_reset_postdata(); ?>
		</div>

	
<main>

	for ( $count = 1; $count <= 4; $count++ ) {

		// Add color scheme setting and control.
		$wp_customize->add_setting( 'showcase-page-' . $count, array(
			'default'           => '',
			'sanitize_callback' => 'absint'
		) );

		$wp_customize->add_control( 'showcase-page-' . $count, array(
			'label'    => __( 'Select Category', 'textdomain' ),
			'type'     => 'select',
			'section'  => 'showcase',
			 'choices' => $option_categories,
		) );
		

		
		

	}