Receipt copy issue

On the 30.12.2018 I went to PEP Maynard Mall, Cape Town to return 2 items and change 1 item. They did not have the item I wanted to exchange for a larger size. The cashier asked if she could keep the receipt and told her I need it to try and exchange the item at a store who has the same stock. She called another lady whom I am assuming is the manageress who told me the same thing. I then asked her what the solution will be and she said she doesn't know because she must keep the receipt. After getting angry, she said I can go and make a copy at a shop in the mall, so I asked her to get her staff to do so and she said they can't do it, I need to go. I reluctantly agreed and asked her for the money for the copy and she said that I need to pay for it. That is when I lost it. After words back and forth She said asked me from which store I had purchased the items and I told her, although the telephone number is on the receipt. She said that she would have to call them and request a copy receipt. I then asked why is it that she couldn't do that at the outset, why did she have to give me such a hard time and then in the end tell me that she needs to call the other branch. If there was a long queue I can understand but there was only 1 customer in the shop at the time. Just terrible service!