Good morning!
Complaining to an access ISP usually doesn't do much good. Even if the IP is not from Korea, China, India or some other country that couldn't care less if one of their customers hacked a site, even in countries like Germany, France, England or the USA there are many ISPs who may give the customer a slap on the wrist - if they do anything at all. Many treat this sort of thing like spamming: not allowed but not our problem.
Banning IPs IMHO is totally useless. Most people in the Web go about their stuff on a dynamic IP. So you'll just be banning the next person who gets that IP, not the hacker himself. Ok, there is more than enough stupidity to go around, but I doubt that too many hackers will be doing there thing with a static IP and will then come back to a site they have "owned" just to gloat.

I wouldn't bother with these methods, but instead try to secure the server as well as I can. Just my two cents...
Regards,
Chris