public function checkBalance()
    {
        $xml = '<?xml version="1.0" encoding="UTF-8"?>' . '<smskredi ka="' . $this->config['auth']['username'] . '" pwd="' . $this->config['auth']['password'] . '" />';

        $response = $this->postXML($xml, 'https://smsgw.mutlucell.com/smsgw-ws/gtcrdtex');

        //Data will be like $1986.0,
        //since 1st character is $, and it is float (srsly, why?) we will strip it and make it integer
        return intval(substr($response, 1));
    }