IP blocking doesn't prevent requests
Flood control is just for failed login attempts and some other stuff like forms being filled out.  It will not keep your bad bot from the site.

Assuming you have an Apache server, you can modify the .htaccess file in the root of your site to block specific ip with the DENY FROM {ip} directive. E.g. adding something like this to the top.

order allow,deny
deny from 255.0.0.0
deny from 123.45.6.
allow from all


If you don't have Apache / .htaccess support, the process will be different.