Came looking for me in the mall after a credit

Purchased item from Eastgate branch. Printer did not print the invoice. They then printed me a duplicate invoice. Went to Randridge Foschini to return the item. The credit was passed and I was refunded. After 30 minutes the Indian lady sends the staff member to come looking for me in the mall outside the store. She then queries the duplicate invoice with me. Eastgate phones do not work. And I have to wait 30 minutes in the store for her to confirm the above with Eastgate. But it's okay to waste my time after you had already passed the credit. You should not have passed the credit in the first place if you thought it was a problem. How do you compensate a client when one gets treated this way?