Returning of Goods

I received a dress as a gift from my aunt in JHB for my baby girl of 18 months old. The dress was specifically bought for a function. i did not have the receipt but the tag and the item was in good condition. when I went to return this item, the 1 manageress says the item is no longer in the store but I saw that they had many of the same. Edgars did not return the item for me only because i didnt have the receipt. we provided them with all the info they required but still was unsuccessful. they tell me that I must do what I want with the item but they cannot return it. I was not asking or any cash money, I had already chosen an outfit to take in place of that item. all they saying to me that i must read they return policy. edgars is not a cheap costing store, yet we support them. Earlier This year I had a similar problem but the staff in the very same branch assisted me. What must i do with an item that is of no use, so in other words I must waste R200 because of a receipt. my aunt used her thank u card to do this purchase and paid the full price of R200. they was making all sorts of excuses that the item was on a 25% discount and so on.