Use Shortcode on Custom Page

You should this way to handle ajax request. It’s the recommended way to make a ajax call in WordPress.

my_function.js
Update your jquery with this code.

jQuery(document).ready(function($) {
    $('#submit_payment').click(function(e){
        e.preventDefault();
        var str = $("form[name=season-form]").serialize();
        //alert(str);
        $.ajax({
            type: "POST",
            url: '//www.example.com/wp-admin/admin-ajax.php',
            data: str + '&action=confirmRequest' 
        }).done(function(data){
            $("#result").html(data);
        });
    });
});

ajax_request_handling
Paste this in functions.php of your theme.

function _myConfirmHandler()
{
    if(isset($_POST['vehicle_no']))
    {
        $vehicle_no = $_POST['vehicle_no'];
        $email = $_POST['email'];

        echo "Your Data: <br>$vehicle_no <br>$email<p />";

    }
    echo do_shortcode('[cfdb-table form="season parking form_copy"]');
    echo do_shortcode('[contact-form-7 id="23" title="Contact form 1"]');
    exit;
}

add_action('wp_ajax_confirmRequest', '_myConfirmHandler');
add_action('wp_ajax_nopriv_confirmRequest', '_myConfirmHandler');

For more information refer to the link.