Deleted page still showing in menu

I created a menu using wp_list_pages to list all of the ancestors of the current page's parent—siblings, etc. Now my client has deleted a page, and deleted it from the trash, but it's still showing in the menu. No caching software is being used and I've flushed the permalinks multiple times. Any thoughts?

function my_page_tree_function() {

`$ID = get_the_ID();`

	`$children = get_pages('child_of='.$ID);`

	`$ancestors = get_post_ancestors($ID);`

	`$ancestors = array_reverse($ancestors);`

	`$ancestors[] = $ID;`

	`global $post;`

	`$subpages = wp_list_pages( array(`

		`'echo'          =>0,`

		`'title_li'      =>'',`

		`'depth'         =>2,`

		`'child_of'      => ( $post->post_parent == 0 ? $post->ID : $post->post_parent),`

	`));`

		`if(!$ID->post_parent):`

//echo '<h5><a href="' . get_permalink($ancestors[0]) . '">' . get_the_title($ancestors[0]) . '</a></h5>' . "\n";

$pages = get_pages('sort_column=menu_order');

foreach ($pages as $page){

if (!in_array($page->post_parent,$ancestors)){

$exclude.=','.$page->ID;

}

}

echo '<nav class="school-menu"><ul class="subnav caps none">' . "\n";

//echo $subpages;

wp_list_pages('title_li=&depth=2&child_of=' . $ancestors[0] . '&sort_column=menu_order');

echo '</ul></nav>' . "\n";

		`endif;`

}

add_shortcode('my_page_tree', 'my_page_tree_function');