Worn out bed!

In less than two years, this mattress has lost total support. This was supposed to be a firm mattress but it has lost the firmness that once it had when it was brand new. After about 8 months of use, I called the company to complain that the center of the mattress had worn out by almost 3" but the response was that it has to be more before they can consider a return. I wake up with body discomfort, back ache and unrestful. Absolutely the worst mattress ever.