You can ban him by doing something like this
iptables -A INPUT -s 90.153.128.13 -j DROP
Your server will appear as 'down' to that IP address until the next time you reboot it. If you want to do it permanently, you'll have to do a little more magic.
This will only be effective if he is spamming from one IP. You'll have to add one line for each IP. If he is doing something like a DDOS scrape (multi-IPs) you're outta luck.
I recently had my black hat bullshit content site scraped via a zombie network. IPs were everywhere. I just disabled the site for 24 hours and redirected all traffic to fbi.gov. I've heard of other people doing this. I'm sure it doesn't help but it did stop the attack.