public function getStatus()
    {
        if (null === $this->username || null === $this->password) {
            throw new Exception\InvalidCredentialsException('No API credentials provided');
        }

        $res = $this->getAdapter()->getContent(self::SMS_STATUS_URL, 'POST', $headers = array(), $this->getParameters());

        return $this->parseStatusResults($res);
    }