Complaint Review: Food For Less

Every two weeks, I take my mother to this Food For Less to do her grocery shopping.  She spends an average of $350 a month.  Last month, my mother was overcharged $6 on her total bill.  When we returned two weeks later, my mother presented the big tall black man in charge(manager?) with a receipt.  He would not refund the money owed her.  

My mother then asked for him to credit the $6 on her current purchase.  He refused.  My mother left a $100 worth of groceries on the belt and walked out.  Is it common practice for this Food For Less to steal money from senior citizens on limited income and ripoff customers?  The big tall black man is a scumbag.

Note:  The groceries that were overcharged were still on sale at the time the receipt was presented for a refund.