Bad customer service

Yes 31st January 2023 I bought groceries at Gelvandale Spar in Port Elizabeth. I asked the cashier for R1000 cash back. She gave me a long explanation of why she couldn't give it to me. I then asked her to call her manager. A customer behind said he wanted R250 which she gave to him whilst I waited for the the manager. She also gave another customer R150. When the manager came he also gave me a explanation why the cashier couldn't give me the money. After the explanation she gave me R700 and I had to buy a plastic bag to get the cash back . So R250 +R150 +R701=R1101. Why could she not give me the R1000 in the first place.