CLICKS ATTERBURY - BAD EXPERIENCE

I went to Clicks Atterbury today to exchange an item for the exact same item. During this process I did not present the attendant with my clicks card. After I left the shop, I realized that I forgot to buy toiletpaper. I went back to Clicks. When I got to the till, I presented my clicks club card and informed the attendant that I would like to use my cash back whereafter the attendant informed me that if your card has been used twice on one day, u cannot use your cashback and you can only use it the following day. I told the attendant that I didn't use my card the first time of the exchange. She told me that they got the details from the slip. I find this very unreasonable and upsetting. How does that work that if your card was scanned more than once, you are not allowed to use your cash back. This is very frustrating.