Don't return it yet. You haven't bought a lemon; you've just entered the "Break-In Period."Explore the data below to understand how to hack the process and enter the "Goldilocks Window."
It's not just the mattress relaxing; it's your muscles un-learning years of bad posture ("Learned Misalignment").
New foam cells are rigid. Sleeping isn't enough. You need concentrated pressure (crawling) to force the layers to open up.
Click repeatedly to simulate walking/crawling on your mattress.
Memory foam is temperature-sensitive. In a cold room, polymers tighten. Control your thermostat to control firmness.
Standard operating temperature. Balanced support and comfort.
Many "mattress failures" are actually foundation failures. Modern hybrids are heavy and need rigid support.
What is your mattress sitting on?