Selling 2nd hand goods qs if new and for new goods prices

Bought a very expensive lounge suite a week or so ago. Upon delivery we showed them some loose stitching. It was noted on all documents and assured it would be changed for another one. When they came few days later they wanted to take it in for repairs. We said no, qs we bought a new lounge suite and expected a new one. It was understood and assured to be sorted. Today we were contacted to pay in another amount at the branch as they want to change our suite with a new one. After a huge fight we were advised that the reason we got this on q discounted price is because this lounge suite was the one on the floor. All lies qs we had to wait for delivery from the warehouse. And we would never have paid this much for a 2nd hand lounge suite