Sleeping on lumps and valleys

We use this mattress 6 months of the year and have already asked for it to be inspected once after 3 yrs while under warranty because the pillow top is so uneven and lumpy where we sleep. The gentleman who inspected said it met the criteria to be replaced but then I never heard from Rooms to Go again. When I called to see when they would be replacing it they said it did not meet the criteria. Now, another 3 years later I can no longer use this mattress but have read so many negative things about warranty and proration I feel it unless to ask for another inspection. However, I wanted to review this mattress, the Woodcrest, and say I am definitely not happy with it. While it looks like a new mattress its miserable because the middle is high and the sides where we sleep are low and lumpy. For what we paid for it at Rooms to Go this mattress should have lasted way past its 10 yr warranty.