Worst 2k+ spent

I wanted a mattress that would comfortable and make sleeping enjoyable. Visited the store and all high-tech gadgetry impressed (fooled?) me and it really felt nice and I forked $2400 for them. One year later I moved to another place (the mattress was well tied in the moving truck -- took help of professional movers). And 4-5 months later it started sagging and it has gone worse since then. I have slept on some cheap mattresses and they have better support even after 3-4 moves than this pricey ones. I can't change it because it has a stain on the side. I absolutely hate this mattress and by extension this company.