Ok it's hard to redeem a roblox gift card first time u assume. I had a really hard time. What you do is add the giftcard right I assumed you already did that. Then you have to go back and buy robux select gifts card It will seem like you are doing it twice. You have to add it then you have to checkout with it.
I'm not sure you need to go to customer service at Walmart and see if someone their can help you.
Go back to the store you bought it from, ask to speak with the manager. Have proof with you that you bought it there.
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