ATT.net private blacklist

Greetings,

We have somehow fallen into the private blackhole list maintained by att.net at blacklist.mail.ops.worldnet.att.net

I have tried for the last two days to approach ATT via phone and email with no response whatsoever. abuse@att.net, abuse_rbl@att.net, and several addresses pulled from ARIN and NetSol lookups have not yielded any response. The calls I have placed have resulted in me leaving a message that was never returned and several instances of "Try abuse_rbl@att.net". None of these are working at all. On top of that, there is no page or FAQ pertaining to blacklist.mail.ops.worldnet.att.net
  (at least, not one that is readily apparent to myself or Google).

If there are any ATT.net admins here, or someone that may have some contact information of said admins, I would appreciate an email or a call.

Thanks!

~Ben