Magento2: How to override the Magento\Payment\Gateway\Command\GatewayCommand?

Because I want to send Notification with response error code by Payment Gateway) when transactions are isValid. And I found the Magento\Payment\Gateway\Command\GatewayCommand do the command with Payment Gateway.

below is my app\code\My\PaymentFaildNotification\Gateway\Command\GatewayCommand.php file.

public function execute(array $commandSubject)
{
    // @TODO implement exceptions catching
    $transferO = $this->transferFactory->create(
        $this->requestBuilder->build($commandSubject)
    );

    $response = $this->client->placeRequest($transferO);
    if ($this->validator !== null) {
        $result = $this->validator->validate(
            array_merge($commandSubject, ['response' => $response])
        );
        if (!$result->isValid()) {
            $this->doNotification($transferO->getBody(), $response)
            $this->processErrors($result);
        }
    }

    if ($this->handler) {
        $this->handler->handle(
            $commandSubject,
            $response
        );
    }
}

private function doNotification($request, $result)
{
    .......
}

And My app\code\My\PaymentFaildNotification\etc\di.xml is just like below:

<?xml version="1.0"?>
    <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
         <preference for="Magento\Payment\Gateway\Command\GatewayCommand" 
         type="My\PaymentFaildNotification\Gateway\Command\GatewayCommand"/>
    </config>

And app\code\My\PaymentFaildNotification\etc\module.xml is just like below:

<?xml version="1.0" ?>
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
<module name="My_PaymentFaildNotification" setup_version="1.0.2" >
    <sequence>
        <module name="Magento_Payment"/>
    </sequence>
</module>

And app\code\My\PaymentFaildNotification\registration.php is just like below:

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
\Magento\Framework\Component\ComponentRegistrar::MODULE,
'My_PaymentFaildNotification',
__DIR__);

After setup:upgrade and setup:di:compile and .... It does'n work. Are there anything setting wrong ? or it can not be override with GatewayCommand ?

Thank you.