[SunHELP] kick spammer

Hi listers,
I just want to hear your suggestion for real world.
I working on the Internet datacenter bussiness.
One of my colocation customer did spamvertize many times ago.
Many complain from Internet, I've told to my boss.
We can only warn to them. I believe they will come back again
in soon. I feel angry that only "WARN" that I can done!!

What all you guy/gal did to handle/fightback with spammer that are your
customers?
Terminate?, pending services?, any limitation?  ....
I really want to hear from you. ;>

Thanks in advances
Have a nice day
Patrick.

REACH is an Asian-focused international carrier 
providing global connectivity services
to carriers and service providers