AT&T nor Apple have given me the promo credits that was mentioned.

The way the promo works, which I have used for past phones is,

You trade in your old device to apple, they give in the trade-in value as a down payment directly to AT&T which is $500, and after 3 billing cycles, AT&T gives the remaining "$500" in credit over 36 months. 

This is not happening to me for the first time, instead, I am being charged the full remainder. 

I agree that the website isn't very clear that you will just get one promotion. Do notice though that at the top of the first screenshot it says you save up to $1,000 by  using the AT&T deal. That implies that you can't save more than that. No one is going to pay you $500 to buy a phone. 

I'm not sure what happens at check out, so there might be more details listed there. 

I think you should complain to Apple about the website being so confusing!

@ATTHelp Apple fulfilled their part of the deal. AT&T did not do their part and give the credits after the 3 months of bill cycles. Stop marking your answer as the solution because it is not the solution. 

@Casinomoney

But it is correct.  You traded in your phone to Apple for a one-time credit of $500. AT&T did not get your trade-in and therefore you are not getting the trade-in deals from AT&T. As ATTHelp wrote, the deals are not stackable (you can't get both).   And if you intended to participate in the AT&T deal you should not have given your phone to Apple for the $500 lump sum.

@formerlyknownas  It literally says in the terms and conditions on Apple website, the promotion deal that the device must be directly traded into Apple. This is not the first deal I have done directly with apple and att, this IS however the first time this issue has come up. 

Again, you did not sign up for the AT&T promo, so AT&T doesn't have "a part to fulfill."

Have you talked to Apple? That's who told you anything about any promo. AT&T hasn't told you anything, except above where they made it clear you didn't qualify. If you disagree, talk to Apple, because that's who signed you up for everything. 

You also clearly stated in your original post that you got $500 off the total price of your phone from Apple.   ATTHelp told you the deal was not stackable.