Contact Walmart and return it or exchange it, nothing anyone else can do for you.
I have did that
You did not say what they said. I don't see how they won't exchange it. But they are the ones that need to do this, we can't help you, you need to deal with the company that sold it to you. If one place did not help you, contact corporate support if the local store did not help for some reason.
Was the box of the tablet in new shape, everything looked sealed properly?