Poor and bad customer service from side step mams mall

On December 2023 I went to side step mams mall to exchange the shoes that I bought on November 2023 and they said there's no size. Early February I went there again and they told me the same thing. So today I was at the store been helped by two ndebele ladies and they said there's no size. I requested a refund nor voucher and said there is no money I must come back another time. The attitude and service that I got from the store I felt disrespected because i asked the lady her name and said there's no need for me as a customer to know her name and I'm full of nonsense bcz she doesn't even know me as their store customer. Isn't fair for me to run around with my petrol for being helped. They both even laughed at me when I asked their names. The other lady said her name is Lindiwe. I am so frustrated bcz my son couldn't wear this shoes on December and now is Easter holidays still he cannot wear them. What is it that I have to do as a customer to be helped in the store. The slip isn't showing very well since it's an old slip. Side step treats customers like trash as if they not running a business. Poor customer service I got. I am not happy at all the service. How long will I hold this shoes on me?