Hi DCGiggles,
I prefer to only answer questions on the forum because that way it can also help others with similar questions or in the same area who can read the questions, comments, and answers and helps make the forum a more useful resource. It also of course saves me from having to answer similar questions many times on an individual or private basis and with the site growing, my ongoing research and conversations with various retailers and manufacturers, and the other tasks that are important to the ongoing development of the site taking up most of my remaining hours (besides sleeping), I am not able to provide any private consulting or replies to requests for help outside of the forum (unless of course a question is not appropriate for public posting or is about issues with the site itself).
There is certainly some truth to what they are saying and there will be a break in and adjustment period with any new mattress over the course of the first few weeks as the materials lose any of their initial “false firmness” and the cover stretches a little and loses any initial stiffness it may have and your body adjusts to a sleeping surface that is different from what it’s used to so it’s not unusual at all that your experience on a brand new mattress will change over the course of the first few weeks (see post #3 here). Mattresses in a showroom will generally have already gone through the break in process.
Having said that … it’s possible (although it’s not very common) that your mattress is different from the one you tested in the store either because the mattress you tested was a different model or because of a manufacturing mistake when your mattress was made.
It may be worthwhile going back to the store and confirming that the mattress you received is the same mattress that you tested in the store (it should have the name of the mattress on the law tag) and to confirm that the store mattress is clearly different from the one you received (although this would also be somewhat subjective).
You are right that the specs you listed don’t say anything about the quality or durability of the materials in your mattress or the mattress “as a whole” but I would also keep in mind that you can’t “feel” the quality and durability of the materials in a mattress because lower quality and less durable materials can feel the same as higher quality and more durable materials in a showroom or when the mattress is still relatively new.
If you have a mattress for example that is made from lower quality and more durable materials and another mattress that is made from higher quality and more durable materials and the type, thickness, and firmness and general properties of the foam layers are the same in both and they both have a similar cover then the two mattresses would “feel” very similar to each other in a showroom or when they are relatively new. The difference is that the mattress with the higher quality/density materials will be more durable and will maintain it’s original properties for longer before the foams soften or break down and the mattress loses it’s comfort and support relative to the person sleeping on it.
Unfortunately this isn’t something that Kingsdown (or your retailer) will be likely to acknowledge and they will probably just tell you that they make a great mattress and you are protected by their warranty even though a warranty has very little to do with the durability and useful life of the mattress or how long it will be before you no longer sleep well on the mattress and decide to replace it (see post #174 here).
Your best odds of success would likely be to talk with your retailer and focus on whether the mattress you tested in their showroom is the same as the one that you received. If the law tags indicate that the mattress you received is different from the one you tested (or that is on your receipt) then of course I would insist that they replace your mattress with the correct model.
If both mattresses are the same model then you would be in a more difficult position but if you have gone back to the showroom and confirmed with some careful testing that the mattress in their showroom is clearly different from the mattress you received and that it couldn’t possibly be the result of the break in and adjustment period on the mattress then I would ask them to come to your home and test your mattress for themselves to confirm that it is clearly different from the one in the showroom. If they confirm this then they should be willing to replace your mattress with the correct mattress. Unfortunately this will rely to some degree on their goodwill and on their willingness to accurately assess and compare your mattress to the one in the showroom.
It may be worthwhile to pursue your request as far up the line of management as possible to see if someone with the authority to do so can make an exception to their policies in your case. I would take a firm, insistent, and “assumptive” tone but maintain a respectful and polite approach since you are looking for an exception based on somewhat subjective issues and not for them to do something that they really would have have any obligation to do (unless all the evidence points to your mattress being different from the one you tested or that is listed on your receipt).
Don’t forget that it wouldn’t be unusual for them to hear the same complaint from many customers that don’t realize that a new mattress will feel somewhat different from the one they tried in a showroom and that in most cases these types of issues generally resolve themselves just by sleeping on the mattress for longer so they may “lump you in” with many other customers that say the same thing where their complaint may not be as legitimate as yours (assuming that your mattress really is different),
Because you can’t “feel” the quality of the materials in a mattress the only way to avoid making a purchase that uses lower quality materials that are more likely to soften or break down prematurely and all the issues that goes with it is to make sure that your retailer or manufacturer can provide you with all the information you need to make an informed choice (see this article) before making a purchase so you can avoid them in the first place.
Phoenix