No exchange service

I purchased a dress on 3 January 2019 at PEP Stores as gift for my niece. I returned it to PEP Stores Signate Terrace on the 5 January 2019 to exchange for a size smaller. All tags was on the dress. I could not find my receipt and was told very abruptly we do not do exchanges without a receipt since 2018. I had no time to offer an explanation or to say it is the same item i want just for a smaller size. The consultant carried on serving another client ignoring me. I left the store with the item.