Refusal of Exchange

Hi there, I made a laybuy in February this year at Dunns in Motherwell in Port Elizabeth then I paid up this laybuy by the end of March... Its a dress worth R300 after a week I decided to try the dress on only to find out the dress has a factory fault. So I have never wore it I kept it with a slip not knowing what to do because it was the last dress.

I have tried to contact Dunns employee Elvis Nduna then he said the only Dunns is near by is in Humansdorp so I couldn't go there, I asked if there is a way that they can do the exchange for me he said NO.

In short, today I have passed by Dunns in Motherwell, found the same dress... New stock, I guess... so I approached a Cashier and explained my Problem She said that is an old case they cannot do anything about it.

When I check on their sleep there is no info about the exchange. Please advise.