Bad attitude by a store manager

On the 6th of February I bought a dressand a top from jet stores and because I was in a hurry I did not fit them. The dress did not have a tag and they used another dress of another size so I can get the one I was buying. Today I return the dress to go look for a different size I was told that they do not take used goods. The manager told me in front of customers and staff that I cannot read English,which I was made a laughing stock in the store n just left me another counter with ni answers. I tried to gt him to explain why he was not taking the item back as I had a slip he just ignored me and walked away. Is this how customers are treated in your stores? Ibwas not even buying on credit but cash I guess my money is not good enough n I want this matter resolved or I am taking it further