Simmons Mattress Co. Beauty Rest Defective Mattress Internet

I purchased my 2nd Simmons Beauty Rest mattress in February 2012 to replace my 12 year old mattress.  Within 4 months, the new one started to sag and show obvious body impressions.  My boyfriend and I are both small people, so there should be no reason for the body impressions after such a short period of time.  The corners of the bed are actually raised up and there is a noticeable hump in the center.

I contacted the store that I purchased from and they sent employees out to measure the depth of the sag.  The method of measuring makes no sense, as it is done with no weight on the mattress.  A ruler was placed across the bed and a tape measure was used to determine the depth of 3/4"
They returned to the store and contacted Simmons, who advised this isn't a warranty situation and is considered normal wear.  My previous mattress didn't sag until it was 10 years old, which is what I would consider normal wear.
The store owner said there is nothing more he can do, and recommended that I rotate the mattress 1/4 of a turn every couple of weeks.  As silly as this may seem, I have actually been trying it to no avail.

I am currently waiting on a response from Simmons.  I can no longer sleep in my bed, as I toss and turn and wake up feeling like I was hit by a bus.  Based on the number of poor reviews, I am not optimistic that this company is going to honor their warranty.