public function execute()
    {

        $this->_orderFactory = $this->_objectManager->get('\Magento\Sales\Model\OrderFactory');
        $this->_checkoutSession = $this->_objectManager->get('\Magento\Checkout\Model\Session');
        /** @var \Magento\Sales\Model\Order $order */
        $order = $this->_objectManager->create('\Magento\Sales\Model\Order')->load(
            $this->_checkoutSession->getLastRealOrderId());

        /** change payment status in magento */
        $order->addStatusToHistory('pagseguro_cancelada', null, true);
        /** save order */
        $order->save();

        return $this->_redirect('/');

    }