Was sold the wrong item - Consumer Complaint for Bradlows - Head Office

I went into Bradlows in Nelspruit, I showed the person which bed I wanted a Sealy trivoly bed with a flip top and showed him a photo and he took me to a trivoly bed same size and color but not exactly same as the Pic and since I believed he was an expert and knows their stock I went ahead and did a payment. The bed took long to be delivered and then I only realized a day after that the bed I received actually is not what I wanted. So they made me pay for a wrong type of bed and now they don't want to exchange it because they say I had already opened the bed and used it. But it was their fault I bought the wrong one in the first place. Now the bed is not comfortable at all and I am frustrated that I can't even look at any Bradlows store anywhere when I pass by. This makes it hard for me to go lay a complain to tell them the bed is not so comfortable because I will be left with no bed once they come take this one for inspection. I will never even recommend someone to go shop at Bradlows ever. Bad service.