WP: get post by slug (post_ID)

function get_post_by_slug($slug, $post_type){
    $posts = get_posts(array(
            'name' => $slug,
            'posts_per_page' => 1,
            'post_type' => $post_type,
            'post_status' => 'publish'
    ));

    if( !$posts ) {
        throw new Exception("NoSuchPostBySpecifiedID");
    }

    return $posts[0];
}

// get post ID
$post = get_post_by_slug('the_company', 'company');
$id = $post->ID;
// post by ID
$post = get_post( $id );

And why don't you use native get_page_by_path function?

https://codex.wordpress.org/Function_Reference/get_page_by_path