WooCommerce - Do shortcode after given category

<?php
  // WooCommerce - Do shortcode after given category
  add_action( 'woocommerce_after_main_content', 'my_action' );
  function my_action() {
    if (is_product_category()) {
      global $wp_query;
      $cat = $wp_query->get_queried_object();
      $cat_id = $cat->term_id;
      switch ($cat_id) {
        case 21: // my category id
          echo do_shortcode('[product id="1801"]');
          break;
        default:
      }
    }
  }