Send order to delivery service based on order status in Woocommerce 3

My orders are automatically sent to the external delivery service. But when the status of the order changes, it is again sent to the external delivery service. How to fix it?

add_action( 'woocommerce_order_status_changed', 'order_stock_reduction_based_on_status', 20, 4 );
function order_stock_reduction_based_on_status( $order_id, $old_status, $new_status, $order ){
    // Only for 'processing' and 'hold-on' order statuses change
    if ( $new_status == 'processing' || $new_status == 'hold-on' ) {
        // Checking if this has already been done avoiding reload
        if (get_post_meta($order_id, 'delivery_order_id', true)) {
            return; // Exit if already processed
        }
    }

    $order_data = $order->get_data();

    // Send data
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, "https://app.example.com/api/index.php?new_order");
    curl_setopt($ch, CURLOPT_FAILONERROR, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($ch, CURLOPT_TIMEOUT, 30);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    $result = curl_exec($ch);
    curl_close($ch);

    $decoded = (array) json_decode($result);

    // Output
    if( isset($decoded['result']) && $decoded['result'] == 'success' && isset($decoded['order_id']) && !empty($decoded['order_id']) ){
        update_post_meta( $order_id, 'delivery_order_id', esc_attr( $decoded['order_id'] ) );
    }
}