Return Refusal

I purchased a Foam Cleaner from Matrix in Constantia Kloof. I found that I already have a new one so tried to return the one recently bought. I was refused the return on the basis that it is a consumable due to it could have been used. I offered to take the can that I have been using to prove that I haven't used the one I was trying to return. I purchase many other aerosol sprays and don't have such an issue to refund an item. This is the first time I heard of such a thing. It should be my consumer right to return the item as it isn't a perishable item. Very disappointing & matrix has lost a customer..