It was great until it wasn't - after 7 years

I am a side sleeper average weight 230lbs. This mattress was amazing for the first 7 years - it was soft but supportive and I never woke up with any pain. I felt like paying almost 3 thousand dollars for a mattress was ok because it had a 15 year warranty. Two years ago I noticed that moving out of my regular spot involved a lot of effort and since then it's become clear that even though when no one is on the mattress it's level, the areas that we sleep on have become so much softer than the area around them that it's liking sinking into a hole. But a finer reading of the warranty doesn't cover this increased softness, there has to be a visible depression. They know exactly how to make it seem like they've got a good warranty while not covering the most common defect. 7 years is not enough for what I paid for it. And they won't even respond to my warranty inquiries. I don't know if its all latex mattresses or just this brand, but I would recommend avoiding them.