Dirty clothes at foschini

I purchased a garment in hurry and dis not check the garment properly as I was in a hurry. Also, should it be common practice to check the garment for stains?especially when purchasing from a large chainstore such a Tgf. 2 days later I went to return the item and the store manager refused to return the item. Claiming and persisting that I used the item. However, the cashier also did not check this item. Now in the store we see there are multiple stains on the jacket. They are not helpful and just walk away.