Show hide payment methods based on selected shipping method in Woocommerce

I would like to hide some payment method and enable another one when I select a specified “Shipping Method" in flexible Shipping plugin form wpdesk.

I have already tried that code:

add_filter( 'woocommerce_available_payment_gateways', 'gateway_disable_shipping_326' );
function gateway_disable_shipping_326( $available_gateways ) {
    global $woocommerce;

    if ( !is_admin() ) {
        $chosen_methods  = WC()->session->get( 'chosen_shipping_methods' );
        $chosen_shipping = $chosen_methods[0];

        if ( isset( $available_gateways['payment_method_cod'] ) && 0 === strpos( $chosen_shipping, 'flat_rate:6' ) ) {
            unset( $available_gateways['payment_method_cod'] );
        }
    }
    return $available_gateways; 
}

and this one

function my_custom_available_payment_gateways( $gateways ) {
    $chosen_shipping_rates = WC()->session->get( 'chosen_shipping_methods' );
    if ( in_array( 'flat_rate:6', $chosen_shipping_rates ) ) :
        unset( $gateways['payment_method_cod'] );
        endif;
    if ( in_array( 'flat_rate:8', $chosen_shipping_rates ) ) :
        unset( $gateways['payment_method_przelewy24'] );
    endif;
    return $gateways;
}

add_filter( 'woocommerce_available_payment_gateways', 'my_custom_available_payment_gateways' );

The link to my website: [www.dajati.pl][1]

The following code example will enable / disable payment gateways based on chosen shipping method.

In this example, we have 3 shipping methods and 3 payment gateways. Each selected shipping method will enable only one different payment gateway.

add_filter( 'woocommerce_available_payment_gateways', 'payment_gateways_based_on_chosen_shipping_method' );
function payment_gateways_based_on_chosen_shipping_method( $gateways ) {
    // Get chosen shipping methods
    $chosen_shipping_methods = (array) WC()->session->get( 'chosen_shipping_methods' );

    if ( in_array( 'flat_rate:12', $chosen_shipping_methods ) )
    {
        unset( $gateways['bacs'] );
        unset( $gateways['cod'] );
    }
    elseif ( in_array( 'flat_rate:14', $chosen_shipping_methods ) )
    {
        unset( $gateways['bacs'] );
        unset( $gateways['paypal'] );
    }
    elseif ( in_array( 'free_shipping:10', $chosen_shipping_methods ) )
    {
        unset( $gateways['cod'] );
        unset( $gateways['paypal'] );
    }

    return $gateways;
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.