A big department store refuse to reissue me the promotion card

[Michael Stole]

I got a promotion card (similar to a gift card) from a big department store half year ago when they had a promotion (spending $5000 and get $600 back in a promotion card). The promotion card has a expiration date, and I used it right before the expiration date. However, they cancelled the order, and now refuse to return or reissue a new card.

I talked to their manager, and they just refused it. I seems that I can not get a satisfying answer from the store, and I need to get help from a third party. I am thinking of BBB. What else can I do? Any suggestions are highly appreciated.