I purchase a new mattess due to a back injury in 2000 and paid 1300 for the mattess which was supposted to be a top of the line Sealy mattress. Now this was purchased to help my back in which I had ruptued a disk and had two bulging disks the year before. Within 6 months I noticed a sag which continually got worse. It's now 2008 and I've exchanged the bed 4 times, I've currently owned a Steans and Foster, Sealy, and Serta mattresses and they have ALL sagged very badly. I now own a Serta and it's been the worse. I received in 6 months ago and my boyfriend and I cannot sleep in it! We both wake up with sore backs and my hip and shoulders now hurt from it. I am at a loss! I don't know what to do, I know if I get another bed it's just going to do the same thing! Having a bad back I need a good bed, now I feel stuck. Please help!