Walmart review: Self check customer service

Today I was checking out my own groceries at Sedalia Walmart and asked for cash back in the amount of 100. That is an option given on the register. The machine had a malfunction and showed it was not able to give me cash back along with a receipt showing this . The lady that came over ( older lady with very short hair and I have seen her there for years)was extremely rude and acted entitled thinking she was a cashier and above everyone else which is typical for this particular store . I tried showing her that she held the receipt showing the amount and she questioned me as if I was trying to get over on Walmart? Why would you treat a customer this way? I also held my own receipt for which she never asked for but I did produce to a subsequent employee showing I should have gotten 100 dollars I asked for a manager and another Cashier came. Very sweet natured lady and she took care of everything . She was SO NICE : this store has some very rude employees . Very rude! Enough to notify the main location about it. The very rude cashier came over to me after I asked to not deal with her again and said the machine I was on was out of 20 dollar bills . She was a horrible example of an even mediocre customer service representative. She thought as a Walmart employee she was not held to the standard we all are when dealing with the public. She was an embarrassment for Walmart in Sedalia .