How do I stop a subscriber re-subscribing?

I currently have a subscriber who has consistently broken the user agreement of my site.

I can cancel his subscription but how do I prevent him from subscribing again in the future?

How would I block his email, IP or Credit card etc?

Is this something I can do through s2member or something that I need to arrange in PAYPAL?

I recommend that you block this visitor to prevent unwanted interaction with them in any way. You can accomplish this with the .htaccess file in your WordPress directory.

Add these lines to the top of the file, where 1.2.3.4.5 should be replaced with the IP you want to block (and you can add a new line like this for each IP you want to block from the site in the future).

order allow,deny
deny from 1.2.3.4.5
allow from all

See also: http://wordpress.org/support/topic/block-ips-with-htaccess