Plushest Mattress Sleeps Hot&Hard - Different From Showroom

We felt very confident with our purchase after spending more than an hour in Quality Sleep Shop's showroom testing their "plushest" mattress. However, the mattress we received is hard and hurts our sides. It does not feel at all like the mattress that we tried. Also sleeps very warm. They sent us a foam topper which helped a little for a couple of months but that is worn down now. This is the second mattress we bought from them. The first one had the same problem - so different from the one we tried in their showroom. Because this process has taken more than 90 days they said that they can no longer resell it so we are stuck with it. (I was shocked to hear that they resell used mattresses - disgusting!!). What's the point of trying out the mattress first if it feels nothing like the one you tried!? And you have to hope you don't get someone else's used one! It's a shame that they didn't stand by their product. I recommend buying a mattress online from one of the many companies or Costco who stands by all of the products they sell.