Decofurn in store displays are misleading, the quality of the product that was displayed in the store is different from the one I bought.

I bought a Deco supreme mattress on 24 November 2019 at the Decofurn in Kenilworth. The one that was displayed in the store was very soft and a bit light, not heavy. When I got home I noticed that the one that I got from their warehouse was very hard and heavy that I cannot even lift it up. The one displayed in the store is a foam mattress and I do not know what material they used on the hard and heavy mattress they gave me. I went to the store in Mid December and told the manager that I was not happy about the mattress and I asked him to come to the floor so I can show him that the one that they have displayed is different from the one I got. The store manager told me to come back in January so he can contact the supplier. I came back in January with the proof of payment and no supplier contacted me. Since they had been delaying to arrange with the supplier to change the mattress I went back to their store to purchase an Air gel memory foam mattress because I couldn't sleep on the hard mattress anymore. On the day I went to buy the second mattress I spoke to Mark the salesperson and to the manager again, they asked me to give them the receipt of the mattress I bought in November and they made a copy of it and promised they will contact the supplier. After a month I called the store and spoke to Mark and he promised that he would contact the supplier and get back to me, today is the 14th of May I am still waiting and nothing has been done.