WOOCS - WooCommerce Currency Switcher

Plugin URL: https://kybernaut.cz/pluginy/woocommerce-pay-for-payment/

In file wp-content\plugins\woocommerce-pay-for-payment\inc\class-pay4pay.php add next code:

if (class_exists('WOOCS')) {
    global $WOOCS;
    $cost = $WOOCS->woocs_exchange_value(floatval($cost));
}