Thanks for the update. I was in the same boat yesterday, saw your post and went to my local AT&T store. They said they couldn't change programming there, that's only possible at their "Hub" stores. My area Hub store was already closed for the day so I went home and took on the hour+ slog of finding a rep by phone who could help me.
It turns out that the execution of this deal between NFL and DTV failed miserably, and the rep told me her supervisor was at his computer manually programming ST Max for season ticket holders who were offered this promotion. This morning my account had a charge on it of $395.95 for ST Max, then two $100 credits for ST Max and another credit for $95.94, the net result being ST Max for $100 as per the offer.
ST Max for $100 is a nice perk as a Bills season ticket holder, but when they don't process it within 5 days as they say they will, it creates a lot of extra work and stress.