public function cancelPayment($merchantPaymentId, $paymentType = 'web_cashier')
    {
        $endpoint = $this->endpointByPaymentType($paymentType, $merchantPaymentId)['endpoint'];
        $url = $this->endpointByPaymentType($paymentType, $merchantPaymentId)['url'];
        $options = $this->HmacCallOpts('DELETE', $endpoint);