I had a very similar experience as Al (http://www.ripoffreport.com/reports/0/284/RipOff0284607.htm). Strikingly similar which gives me great confirmation.
My Serta mattress blew out over the course of a few years, that is fine, no big deal. When I called American Mattress to ask about my warranty, they never called me back. I hounded and hounded, and finally got them on the phone.
They told me how to measure the sag to determine if I qualify for a new one, I did. They required another $50 to come measure themselves. The guy showed up with an unmarked truck and no uniform. My mattress passed the test in terms of SAG, I saw him measure.
Then no call, no call, no call. Finally I got them on the phone, and they acknowledged that it did have enough sag (>1.5") but that light stains put me out of warranty.
They got more of my money, wasted tons of my time, and I think were deliberate in ignoring my calls. These guys are the definition of greedy salesmen.
Bill
Chicago, Illinois
U.S.A.