The Gelmar manager have refused refund and is not following the CPA

I have visited Gelmar Arbour on 12 December 2020 and bought few items there. On arrival home I have found to have a stock of previously bought items from another supplier and decided to return some of items but I could not find my previous slip. I have told the manager by the name Dilan that he may re-print it as I have used a credit card for that purchase. He also refused to issue voucher to the value of the goods that may use it later at the shop close to my home. He claimed to follow company policy but why they have return and refund counter? Why they are not following the Customer Protection Act (CPA)? I have found that his attitude was of questionable competence. Why they employing *********** staff?? Why they are not BBEEE compliant as it looks to me that all staff are Indians??