Kingsdown Body System Mattress Review

About 4yrs ago my husband and I purchased a Kingsdown body system mattress. The sales rep talked very highly of the Kingsdown mattress and also said he had one. So we tried it out and thought it was comfortable.We purchased the mattress and box spring,thinking we got a high quality product. However, after 4yrs the mattress is sagging. I called or mattress company where we had purchased it. So they sent out a tech to check the mattress out. He took pictures and said they would get back to us. In a week I was contacted by the mattress company, she told me that the bed is sagging but Kingsdown will not cover the warrantybecause there is a stain on the mattress.We did not know there was a stain on the mattress because it was so small and on the outside edge.So we decided to Kingdown.Well that was a mistake!!!!! When I called, Ispoke to the manager her name was Jenn.I told her that the mattress company told me that Kingsdown will not cover the warranty because of the stain even though the mattress is BAD. She told me she would look into it. I asked her how long will this take because my back is really hurting from the mattress. Her response was well I don't know. I asked could you please make this a priorty, but she couldn't give me a definite answer. A week went buy I had to call them.Again I talked to the manager jenn.I asked if she received the pictures. She said yes and and further review they would not cover the warranty because of the stain.So I asked her how can a small stain make the bed sag in the middle when the stain is on the edge of the bed. She said the stain could have broken down the fibers in the mattress. Then I asked her since the bed is only 4yrs old can Kingsdown help us out with another bed. Of course her response was NO she had poor customer service skills and she could have cared less about our problem.We would not recommend a Kingsdown mattress to our worst enemies. So pass the word Kingsdown also goes under a different name called SLEEP TO LIVE. How do we know that? My husband and I just purchased a new bed and the sales man told us that sleep to live is a Kingsdown product.