Poor Customer Service

After my child pain his packet of Dorito chips with a R50 he was on his way out when I was called by the manager infront of a lot of clients in the shop. He accused my child that he did not pay for the chips. Then he showed the slip he received at the till and even the change he received. The manager only looked at it and walked away without even apologizing or anything he just turned his back on the child and walked away. This was very imbarrasing for the child and how he approached the child and his response was very unproffessional