$200 special credit

Doesn’t sound like there is anything to rectify. If the chat rep is right, each line is eligible but only one line can get it.

Sounds like one of those things where you should have taken a screenshot/photo of the offer, including any place where it said 'see all the details', to expand all the fine print, so that you knew that you complied with whatever the offer was.

You have 14 days to return any devices. There would be a $55 restock fee if any boxes are unsealed.

AT&T is offering you a $200 perk to put you under a 36 month installment agreement which ties you to them for 3 years.  Maybe you had no intention of leaving AT&T, but this locks you in 

Same! I just wasted an hour chatting and calling AT&T reps who say they can't apply it or get me to anyone who can explain how one can "Enjoy an extra $200 off when you upgrade"  

Frustrating, particularly when you can't reach ANY American at American Telephone and Telegraph.

Here's the screenshot!

Is that for wireless or Internet?  

Okay so you have a screenshot what happens if you click on the link?

absolutely.nothing.happens.

You are given the sales page to choose a phone and the checkout process, which DOES NOT confirm anything except the collection of sales tax... and makes no reference to the "extra $200 off" 

Hmmm.  Well that’s bizarre, and not how it should work.   I’m at a loss