public function unbindService($runlevel, $name)
    {

        // stop the service instance
        $this->runlevels[$runlevel][$name]->stop();

        // unbind the service from the naming directory
        $this->getNamingDirectory()->unbind(sprintf('php:services/%s/%s', $this->runlevelToString($runlevel), $name));

        // unset the service instance
        unset($this->runlevels[$runlevel][$name]);

        // print a message that the service has been stopped
        $this->getSystemLogger()->info(sprintf('Successfully stopped service %s', $name));
    }