Durability Issue but Good Customer Service

I've now had this bed for about 10 months so I feel I'm now qualified to write a review. I find people write reviews too quickly (within the first month) and we never get to find out about one of the most important issues, durability. Being a bigger guy, durability in mattresses have been a big concern for me as they tend to lose their firmness over time. My last mattress lasted 4 years but developed a 1 inch dip in it that was very uncomfortable. When I tried to use the 10 year warranty, I was told the dip wasn't big enough, it had to be at least 1.5 inches, go figure. I decided it was time to invest in a mattress that would hopefully last me a lifetime (or a much longer time). I bought this bed at the Calgary Stampede in July 2013. My wife liked the Martinique as it was a little softer (but still firm), and I liked the Paradise. At a price of $5,500 it was too steep for me for a bed, so the sales guy mentioned we could buy the floor model for $3,500. The floor model is made specifically for each trade show and is only two weeks old at the end of the show, so it's the exact same bed as if I ordered a new one. My only issue was it was the king sized Martinique (or more accurately, two twin sized Martiniques) and I felt the Paradise might be the better bed for me as I like a firm mattress. I expressed concerns that it might be too soft for me over time. he said no problem, if it ever gets too soft they would send me out a Paradise no matter how long I've had the bed. Coupled with the lifetime warranty I felt this was good protection that if the Martinique didn't work out I could exchange it. So we purchased the floor model. The first 6 months or so were great. I was having great sleeps, no more leg or back pain, sleeping throughout the night. To be fair, my last bed was great at first as well, so it's the test of time that is the question. Unfortunately, the coming months the bed started to soften up on me as the night went on. I found myself beginning to wake up in the middle of the night with back pain. It had become too soft for me in just over 6 months. I tried it a couple more months but my back pain continued. I then contacted customer service so I could discuss my options with them. The first step suggested by them was to try some mattress pads to try and firm the bed up a bit. It took some time for the mattress pads to be sent, and I had to make a couple follow calls and emails, but eventually the mattress pads came. Unfortunately, they didn't help me in terms of firmness. The next step was to send me a Paradise bed which I discussed directly with the President . Although he expressed I was outside the comfort exchange timeline of 30 days, they were able to make an exception for me due to what I was told by my sales guy at the time of purchase. I really appreciate them providing this level of customer service and making things right. I just received the Paradise bed a couple days ago and it's been great the first couple nights. Hopefully this one will hold up, and I'm optimistic that it will as it's their firmest model. I'll update my review at some point in the future to comment on the Paradise's durability. Fingers crossed.