Six days without a refund for a wrong transaction

My daughter bought groceries that went over my bank balance at Shoprite Silverton Pretoria , so I told her to report it. I asked the cashier to cancel it so she could quickly run to the ATM nearby. I was told that the transaction had already taken place and we should wait for our money to automatically return to the Capitec account. We've waited for six days without a reversal and had to go back today, 23rd October, for a refund. I've spent almost 2 hours in the store searching for transactions in their register, and I was told by the cashier that she did not cancel the transaction. After a prolonged wait, I received my cash back and began to contemplate the potential consequences had I not visited the store. This level of service is unacceptable.