$orderId = $number8; //order id
        $order = Mage::getModel('sales/order')->load($orderId); //load order
        $order->setState(Mage_Sales_Model_Order::STATE_CANCELED, true)->save();
        $state = 'canceled';
        $status = $state;
        $comment = "Changing state to $state and status to $status Status";
        $isCustomerNotified = false; //whether customer to be notified
        $order->setState($state, $status, $comment, $isCustomerNotified);
        $order->addStatusHistoryComment("Payment Failed",
            Mage_Sales_Model_Order::STATE_CANCELED);
        $order->setStatus($status);
       $order->save();


        $this->loadLayout();
        $this->_initLayoutMessages('checkout/session')->addError(Mage::helper('checkout')->__($errorMessage));
        $this->renderLayout();

$orderId = $number8; //order id
$order = Mage::getModel('sales/order')->load($orderId);
$order->cancel()->setState(Mage_Sales_Model_Order::STATE_CANCELED, 'canceled', 'Payment Failed', false)->save();