Rocky Mountain Not So High On Big Sur

This is a 'soft side' waterbed with a pillow top. For the first year, I loved this bed. It was firm, but comfortable. I liked the looks and that I could use my regular bedding with it. After the first year, I had to replace the foam inserts and have had to replace them regularly since then. The pillow top sags and wrinkles terribly. The foot of the bed is now firmer than the head, so I feel like I'm always sleeping at an angle, regardless of flipping the foam inserts or adding water to the bladder. I've tried contacting Big Sur and the company that sold the mattress to us to see if there's anything I can do to save it. They can only suggest that I spend another $1700.00 dollars for a new 'soft side' mattress in which to place the existing bladder. Yeah...that'll probably happen. :( Really wish I hadn't spent so much money on this mattress. Looking for some sort of replacement now.