It's their fault that you didn't check the pre-order eligible items and that there is no game you want to pre-order on the list?
Um, no, I think you need to reread the thread. The promo is not working for nearly all the PS4 and X1 games that are listed on the promo page. You have to contact them to get it to work correctly.
Quite contrary to your assertion, I picked out a game and locked in the trade (factoring in the extra $10 or otherwise I wouldn't have bothered) based on the very list itself. There are several things I was considering but none of them work, apparently.
It wouldn't be such a big deal except that Amazon has hidden metrics for customer complaints/CS issues and too many and you might possibly get banned. That was my point - I shouldn't have to contact them (and have it count against me) when it is entirely their fault.
At this point I'm just hoping the list is still up there and hasn't been changed by the time I get my credit (as my game is still on the long, slow process of UPS ground delivery - going on 5 or 6 days now). I guess I should screen capture it just in case but that will make dealing with CS even harder.