HeidiMcHaneyWilson,
We are sorry to hear that your mattress is sagging.
Can you tell us about the base this mattress is being used on? All mattresses need to be used on a properly supportive bed base to maintain their quality overtime. Foam products can soften with time but any softening should be very minimal and gradual. We stand behind the quality of our products and back this mattress with a 10-year warranty against any manufacturer issues or unusual wear in the material.
You can contact us at cs@linenspa.com and we would be happy to help assist you in a return to Home Depot and help you find a mattress that will be a better fit for your needs.
Thanks!
-The Linenspa Crew