Pathetic Service from Decofurn Montague

I purchased a pluto bed with a mattress for my daughter at Decofurn Montague. We sat on the bed instore and the mattress didn't feel that bad. The one we received from them is hard as a rock, it's like laying on the floor. it serves no purpose because the bed is not being used. I contacted them for an exchange. They do not want to exchange or refund because i logged the claim after 7days. Pathetic service! Dont even know how you can sell someone this mattress. You just lost me as a customer!