Same problem for me. My wife and I actually tried 2 different Beautyrest Blacks: A Viola Plush and Orchid Luxury. Both sank in the middle after a month. The worst part is, sleeping in the valley pinches a nerve in my arm, so I wake up about once a night with horrible, burning pain until my arm wakes back up. This doesn't happen on any other bed - and I travel the world for work. I am 165 and my wife is 125 - we are not big people. We were so dismayed by all the comments about Simmons not honoring their warranty that we didn't even try. Say goodbye to your money and a good night's sleep if you buy this worthless POS.