Very expensive disappointment

Purchased this mattress without considering its very expensive price because it was supposed to be an excellent mattress. Took 3 tries to get one that wasn’t damaged. Finally received an undamaged one and followed the rotation directions to assure even wear and break-in. Unfortunately it has two valleys in it in less than 1 year. We rotated the mattress as recommended and it’s gotten to the point where if you lay in the center of the king mattress you will roll right or left but you won’t fall off because the center and the edges are higher than the areas where we normally sleep. So by rotating it as recommended, instead of having one spot that sags there is now two. I’m 6’1” / 220 lbs and by no means overweight. This mattress was purchased with their box springs as we were told otherwise it voids the warranty. Didn’t help prevent the sagging. This mattress is extremely heavy to lift to rotate which is another slap in the face. Don’t waste your money. It’s overpriced, overrated and does not hold up.