Hi,
Sorry you have had the experience that 40% of Americans have... not liking their mattresses. You have come to the right place to learn.
Most of us here found this website while trying to find a good nights' sleep. I have spent 6 years, perhaps $6000, and with trades and swaps have
owned and had in my home 23 mattresses before then giving up and trying toppers... probably 100... all three types: latex, memory foam (tempur material), and poly, in varying thicknesses and densities... on top of various mattresses. Then I gave up and did mattress surgery, and am sleeping for the first time in 6 years.
There are thousands of posts here representing thousands of hours of research, shopping, mattress trials... etc. which I suggest you search out.
The appalling mattress industry tricks and subterfuge are documented here. The stark reality is that until you sleep on a mattress for several days, you don't have a clue what it really sleeps like. For me, they all felt better than what I was (not) sleeping on at home. (Bad back, side and back sleeper... it has taken a perfect combination of just right not too soft, not too hard etc. stack of 4 one inch toppers on my mattress springs for me to sleep).
Search my id shovel99 for some of my history including recent reasonable success in cutting the top off a Serta firm mattress and placing a combination of latex, memory and conventional PU on top. Search also sandman who documented his mattress surgery, and provided some of the best advice. And jimsocal. Their experiences in mattress surgery are saved at the top of the general forum.
Now the briefest summary: we are all different weight and sleep on back, side, both... and have different reactions to the various bedding feels. Some like latex.. it pushes back. Others like memory because it conforms. Memory is hot. Others of us use combinations.
There are several online companies that will sell you a stack of latex or memory foams "in a bag" and will change out the various slabs for some shipping fees... until you get it right.
Can you return your mattress, spend a lot of time researching here, and then proceed? I dont' recall many posts here by people who just went out and bought a latex or memory foam mattress and were "happy." Of course, happy customers won't likely be here.. .they will be sleeping! The whole idea behind "building" a mattress of differing stiffnesses of latex and perhaps 1 inch of memory foam on top is that you can customize the feel to your own particular needs. I have four one inch topper slabs on top of the "skeletal" remains... the springs from a pretty decent quality Serta that I bought on sale at Sears (Firm). Again, find my post. I simple could not have gotten here any other way. All the mattresses (23, including one latex and one memory foam and combinations) all felt great in the store..and hurt at home.
If your mattress is firm... as you describe... you should be able to make it sleepable with 3-4 inches of 1 inch layers with which you can experiment. But yes.. it is a waste to have your expensive "mattress" ( 10 inch slab of expensive latex or part base... ) be performing the function of "springs" from my cheap mattress ($500). But if you cannot return it and don't want so start from scratch... you can at least fix this.
Sorry I don't have more detail for you, but it's here if you look.
There are lots of helpful people here.
PS... you do need to check back, this website does not automatically update you when there are posts to the thread. And when you find a thread, you need to click "see all" or you will miss a significant part of the dialog.
Good luck. And if you have a "comfort exchange warranty" which is customary in the mattress crook industry rather than a straight return for cash, I suggest you scramble on searching this site in a hurry. Even since I have started mattress surgery, just the past 4 months of my 6 year quest, I have tried different layering of perhaps six different 1 inch toppers nearly every night.. until settling in just the last couple of weeks. So it will not be easy. NOw, if you are just like me or Sandman or Jimsocal... from reading the background, you may just replicate what either of us have done and be done with it. You will find all the best cheapest sources in the links. My "perfect" bed totals no more than $1000 before the $184 St. Dormeir wool cover that knocks out the heat associated with the 1 inch memory foam I absolutely must have in my top layer or second layer. Wish I got here before I spent the other $5000 on delivered mattresses and toppers.
shovel99