Getting demo , second hand furniture but paying for new furniture

My fiance bought a lounge suite at Lewis stores. She requested that it be a dark grey. When we received it we were told they had the light grey in the warehouse,since we said we do not want a demo set. We accepted it, when unwrapping we found oil marks and thought welk it might have been die to transport. So 5 months later it just breaks. And we dont use it alot. lewis sorea came to pick it up to send back to the warehouse to get it fixed,due to it being under factory gaurentee. When we took out all the pillows we found the marketing sing of how much it will cost ect,meaning it was a demo set all along. This is unacceptable. How can you make a requeust and pay back so kuch with all the policies,but still not get the value you asked for or ar paying for. So we got a second hand broken set,but paying for a new set.