thermpedic review: bad matress

I purchased a mattress along with other things on Aug 1oth. It was delivered on Aug 14th. The mattress that I was given is hard as a rock. The bed in the store that I tried was soft and a very nice bed. It is mid night and I have to be awake at 4 am but can not even sleep on the bed I was given. I have never been more upset with service in my life. I have not had one phone call back from Conns. I am just told to come back and speak to someone else the next day. I am told that the managers have no say so in what they can do about it. I just dont know what to do. I am not going to pay for something I can not use.