how do i make a complaint after being denied a faulty gift card refund

I'll let you know what most likely happened. You purchased the Gift Card off a rack that is available to the public to tamper with. A scammer grabbed a bunch of Gift Cards off that rack and peeled off the gray sticker and wrote the code down. The stickers are then replaced when ones that can be purchased from Amazon. After they did that, they placed the cards back on the rack and just waited for you to pick one up and activate it through the check stand. By scratching part of the code off, it gives the scammer more time to spend the money before you get a chance to redeem it.

The store failed to protect your purchase and the scam happened right in the store where you bought it. You should never purchase Gift Cards off of those racks and they should only be purchased by retailers who secure their Cards behind a counter. Ironically, some of these same retailers will lock up products that are stolen from them, but when it comes to their customers losing money, they don't seem to care.

You need to first contact the store and it is likely the Store Manager will not be able to do anything, so you then escalate to a corporate office. Every year around the Holidays every news outlet runs stories about these scams and to avoid those racks, but of course it can happen year around and will continue as long as the retailers still sell them that way.

You'll need to take it up with the store from where the card Wass purchased. The store likely sold you a used card.