Uncomfortable and painful

I bought a Restonic Natures Rest bed at OK Furniture this bed is very uncomfortable, the sides are laying in and the middle is a knob looks like a hill. I have back problems and in the morning when i wake up from this bed i have to drink pain meds to clam my back and body pains. I purchased this bed in less than 5 months. I did contact the store but they keep on saying that they are waiting for Restonic to replay them, Restonic does not answer or assistance. I do not want a credit i want a return and a refund.