Item in Picture looks nothing like item sent, Zando refuse a refund

Hi there, I bought a product from Zando. The product came and looked nothing like the item in the photograph. It was discouloured and cheap looking. I Requested a return within the period stipulated and Zando. Zando are returned the item to me stating that I had washed the product. I promise you, I never wore or wash the garment. I put the garment on, Saw the discoloration and immediately put it away to be returned. They are saying the garment was washed. Zando are refusing to take ownership of selling a sub standard product and are making false claims when they say I washed this product. I would be willing to have the product sent away for testing to test if the product has any washing power residue. They are absolving themselves of responsibility for false advertising of a product and not delivering the required item. The picture of the product looks like oil leggings, but it is discoloured. Please help me. It is not fair that because of their size and clout this organization is allowed to take consumers for a ride and lie to get away with it. # ***. I will never recommend using this online platform ever.