REFUSAL OF EXCHANGE OF INCORRECTLY DELIVERED PRODUCT QUANTITY

I have ordered a 100ml Perfume and then BASH delivered a 50ml Perfume instead. I called the customer care for online orders where I was assisted by a lady named Nicole who advised on me sending Photos of the item in my position for the company to arrange courier to deliver the correct item and collect the incorrect item. Today when I make a follow up they insist on refunding me saying their process doesn't allow exchange but their agent said they do exchanges and will initiate it for me. I JUST WANT THE CORRECT ITEM TO BE DELIVERED TO ME AS IT WAS A PRESENT FOR MY WIFE. NOW BASH IS GIVING ME A RUN AROUND!!!