No Returns!!!

I bought a white dress at Canal Walk shopping centre. I decided to return the dress as I didn't really like it and had found what I was looking for in another shop. I tried to return the dress to the Golden Acres Exact shop and I was told that I can't return the dress because it has marks under the armpits (probably from someone trying it on before I bought it). Why have a dress with marks in your shelves if you know very well that you don't accept returns that have marks??!! I'm very disappointed and I will not be shopping at exact again