Dave Lieber of DMN ran a series of articles on this as well, I recommend:
"Watchdog Memo to AT&T's CEO: Didn't mean to get you in trouble" <https://www.dallasnews.com/news/watchdog/2016/07/08/watchdog...>
And:
"Watchdog: AT&T's CEO gets new job, Frontier employees dance during disaster" <https://www.dallasnews.com/news/watchdog/2016/08/04/watchdog...>
At Techdirt: "AT&T Falsely Blames The FCC For Company's Failure To Block Annoying Robocalls " <https://www.techdirt.com/2016/06/02/att-falsely-blames-fcc-c...>
The FCC announcement, voted on June 18, 2015: "Fact Sheet: Wheeler Proposal to Protect and Empower Consumers Against Unwanted Robocalls, Texts to Wireless Phones" <https://web.archive.org/web/20150910081851/https://apps.fcc....> (PDF)