public function getSendStatistics()
    {
        $this->_action = 'GetSendStatistics';
        $this->_method = 'GET';
        $this->_refreshDate();

        $this->_generateSignature();
        $res = $this->_request();
        if ($res['code'] == 200) {
            $result = $res['body']->GetSendStatisticsResult->SendDataPoints->member;
            return array(
                'Complaints' => (string) $result->Complaints,
                'Rejects' => (string) $result->Rejects,
                'Bounces' => (string) $result->Bounces,
                'DeliveryAttempts' => (string) $result->DeliveryAttempts,
                'Timestamp' => (string) $result->Timestamp
            );
        } else {
            return new SimpleEmailServiceError((string) $res['body']->Error->Code);
        }
    }