AT&T has a website/Youtube channel for a lot of their old technology-related videos (e.g., AT&T UNIX, using telephone jacks instead of hard-wiring phone cables in the 70s/80s, etc) and one of them was a video called "The Benefits of a Regulated Monopoly." It was made by Western Electric (a subsidary of AT&T at the time) and tried to convince people that their monopoly over U.S. was beneficial to the company and phone system, although I don't quite remember what their arguments were.
I tried contacting the AT&T Tech Channel through their twitter, but never got a response. I'm not sure of any way I'd be able to contact them, or if it'd even prove worth it, so the last resort would be probably to find someone who ripped the video.
It's the same embedded Youtube video, but there are a ton of comments below it that might have something. I'm looking through it right now, but thought I'd post it here.
Edit: This also shows some timeframes, since it seems like the video was taken down within days, if not within 48 hours. It seems like people started talking about it going private on 18 Dec, and the earliest article seems to be 17 Dec.