Have not received my gift card promotion

I purchased Rare Replay for Xbox One, never had an issue with this last year.  But I have been waiting on my 15 dollar gift card to continue buying games like Madden and NBA 2k but had to go with gamestop since I still haven't received this.  I used to like the Dell deals with the gift card but I have been hearing many people with the same problem lately.  The game was shipped August 4th, it's been a month, don't know who to contact or how to get this issue solved?  I have a feeling there will be something in super super fine print that says I don't get one even tho I preordered that game a month in advance with that deal.