Our new $ 1,800 Serta mattress slumps on both sides, and they will not take it back. We had to buy plywood boards to stabilize it. Our next door neighbors had the exact same problem, and had to also buy a board. We went through Better Business Bureau and could not come to an agreement. Last I looked, Mattress One has a «F» rating with the BBB. The state attorney sent me a request to give them information about this company, so we will see what happens. I will never shop there again, and I would not recommend it.