Comcast postmaster?

[Brian Rak <brak () gameservers com>]

Is there anyone here that can put me in touch with a Comcast mail server 
administrator?  It seems that they've firewalled off some of our IPv6 
space, and I can't seem to find any contact information.

Interestingly, I can't even fill out their blocklist removal form, 
because it only accepts IPv4 addresses.