Checking if customer is login not refreshing

Now I implement the code below

use MagentoFrameworkAppHelperAbstractHelper;
use MagentoCustomerModelSession;
use MagentoFrameworkAppHttpContext as AuthContext;

class Customer extends AbstractHelper
{
    /**
     * @var MagentoFrameworkAppHttpContext
     */
    private $httpContext;
    private $objectmanager;
    private $authContext;

    public function __construct(
        MagentoFrameworkAppHelperContext $context,
        MagentoFrameworkAppHttpContext $httpContext,
        MagentoFrameworkObjectManagerInterface $objectmanager,
        Session $session,
        AuthContext $authContext
    ) {
        $this->objectmanager = $objectmanager;
        $this->httpContext = $httpContext;
        $this->customerSession = $session;
        $this->authContext = $authContext;

        parent::__construct($context);        
    }

    public function isLoggedIn()
    {
        $isLoggedIn = $this->authContext->getValue(MagentoCustomerModelContext::CONTEXT_AUTH);

        return $isLoggedIn;   
    }

But when I refresh my page it still say that it’s login eventhough I already logged out. Below is the code of my template

< ?php
    $customerHelper = $this->helper('VendorModuleHelpersCustomer');
?>


< ?php if ($customerHelper->isLoggedIn()): ?>
    
                        
        < ?= $block->escapeHtmlAttr(__('Account')) ?>
    
    

        < ?= $block->escapeHtmlAttr(__('Logout')) ?>
    
< ?php else: ?>
    

        < ?= $block->escapeHtmlAttr(__('Login')) ?>
    
< ?php endif; ?>