Marshall's Backache Special

We purchased the Serene Rest Assured IV from the Bay 3 years ago. We thought we were buying the best mattress according to the sales person. Price was not an issue, we wanted quality! We spend 1/3 of the year at our winter home so the mattress in theory is 2 years old. We contacted the Bay customer service and an inspection was scheduled. Results the same as all other mattress reviews with problems. Depressions are less than 1 1/2". The 10 year mattress warranty is a joke. My wife and I wake up with a back ache every day. The mattress cannot support our weight and my wife is tiny. You can feel your body sinking when you lay down. I have exhausted every avenue possible with The Bay. Believe me they tried to help us. They went as far as talking to the owners of Marshall. Marshall's response is that the mattress meets specifications. The best thing that could happen is that The Bay drops the Marshall product line. Slept on a Beautyrest mattress in a hotel over the weekend. My back and body was loving the mattress. Another problem was that The Bay sold us a mattress that we did not have to flip. Turns out this mattress must be flipped and rotated. The inspector reported depressions on both sides of the mattress and it was never flipped. Very suspicious conclusion.