On the top of your receipt is the store number to the Walmart that is giving you trouble. Call 1(800) Walmart.
Tell them the store number and your problem. They will take care of the complaint. They send a message to the store resolving the issue and if they don't it will be sent up the chain.
If enough people complain, the more they will try to fix it from their home office. I used to be a salary member of management for Walmart and I left because of a lot of issues of what we can or can't do.