HotPay mobile (direct billing/premiumrate)

$hotpay = $payment->online(
    new HotPayMobilePayment(
        'secret', 
        HotPayMobilePayment::METHOD_PREMIUMRATE OR HotPayMobilePayment::METHOD_DIRECTBILLING
    )
);

$hotpay->setAmount(1.23);
$hotpay->setDescription('description');
$hotpay->setOrderId('orderId');
$hotpay->setRedirectSuccessUrl('https://google.com');
$hotpay->setRedirectFailUrl('https://google.pl');

$hotpayPayment = $hotpay->generatePayment();
$hotpayPayment->getTransactionUrl(); // transaction url