global $wpdb;
$order = new WC_Order( $order_id );

foreach($order->get_items() as $items => $item) {
// get the replacement email
$results = $wpdb->get_results("SELECT product_id, replacement_email FROM {$wpdb->prefix}fulfilment_center_by_product where product_id={$item['product_id']}");

if($results) { foreach($results as $result) { $rep_prodid = $result->product_id; $rep_email = $result->replacement_email;

 if($rep_prodid == $item['product_id']) { $this->send( $rep_email, $this->get_subject(), $this->get_content(), $this->get_headers(), $this->get_attachments() ); }else { $this->send( $this->get_recipient(), $this->get_subject(), $this->get_content(), $this->get_headers(), $this->get_attachments() ); } } } }