public function getValidationFailureMessage()
    {
        $payPalRequest = $this->getPayPalRequest();
        $payPalResponse = $this->getPayPalResponse();
        $shopOwnerUserName = $this->getShopOwnerUserName();
        $receiverEmailPayPal = $payPalRequest[self::RECEIVER_EMAIL];

        $validationMessage = array(
            'Shop owner'           => (string) $shopOwnerUserName,
            'PayPal ID'            => (string) $receiverEmailPayPal,
            'PayPal ACK'           => ($payPalResponse->isPayPalAck() ? 'VERIFIED' : 'NOT VERIFIED'),
            'PayPal Full Request'  => print_r($payPalRequest, true),
            'PayPal Full Response' => print_r($payPalResponse->getData(), true),
        );

        return $validationMessage;
    }