Oh wow. I think we now have an AT&T that's nicer to sysadmins!
AT&T has long been one of the networks I've dreaded running afoul of when sending email newsletters. For years they've been opaque about their process for getting a false positive IP address de-listed from their block list. "Can neither confirm nor deny" is their MO in how they handle this. It has taken me over a month to get a false positive cleared before.
Most networks have a form you fill out, a list of things you have to fulfill to get automatically restored, and some automatically reinstate you with a delay if you even contact them.
I had some email delivery issues with Gmail and needed to make some DNS changes to make Gmail happy, which instantly landed me in AT&T hell. I was expecting a month of neglect. Instead, they replied back within a few days to let me know that my request will be carried out shortly.