Can't exchange item in stock

I returned an item because it was supp**** with UK power plug, which was stated on my return. Takealot says the item has been return to supplier, and they not have stock for exchange. Even though their website still lists the item with stock available. They now say the stock available is from a different supplier (same item, different price). My argument is, that takalot is my supplier, and my supplier site (takealot) still shows stock available, So the item should be returned/exchanged.