Hi Kristen,
I’m sorry to hear about your unfortunate experiences with your Essentia mattress 
There is more information in post #2 here and the more detailed posts and information it links to about safe, natural, organic, “chemical free”, and “green” mattresses and mattress materials that can help you sort through some of the marketing information and terminology that you will encounter in the industry and can help you differentiate between them and answer “how natural is natural enough for me” or “how safe is safe enough for me” so you can make more “fact based” choices on the types of materials you are most comfortable having in your mattress. These types of issues can be complex though and are generally specific to each person and their individual sensitivities, circumstances, criteria, beliefs, and lifestyle choices and can have more to do with your specific sensitivities than with your mattress.
While I agree with you that the claims that Essentia makes on their site are questionable at best and misleading or even deceptive at worst … it doesn’t sound like you have any certainty that you are reacting to the materials in their mattress and it’s possible that there could be other reasons for your symptoms. The only reliable way to assess the “safety” of the materials in a mattress are based on lab testing for harmful substances and VOC’s but unfortunately in some cases there are some people that may be more sensitive than the testing limits that would be “safe” for most other people so even with testing there is no absolute certainty that a particular person won’t be sensitive to a specific substance in a specific material.
I don’t know of anyone that has received a refund in circumstances similar to yours but of course that doesn’t mean that there haven’t been. I’m also not a lawyer so I can’t provide any legal advice and it would be much better to contact a lawyer in your area to ask for a legal opinion about whether you would have any recourse in your specific circumstances but after 2 years I would “guess” that it’s unlikely that you would be able to receive a refund unless they were willing to make an exception for “goodwill” reasons.
Before I went to the expense of hiring a lawyer though I would keep on trying to connect with them and explain your circumstances and let them know what you are planning to to do and see if they are willing to offer any suggestions that may help you. 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. I would take a firm, insistent, and “assumptive” tone but maintain a respectful and polite approach since you are looking for an exception and not for them to do something that they really would have have any obligation to do.
I would also follow up with your doctor to find out if they can provide any guidance about whether your symptoms may be related to your mattress and see if they have any suggestions or tests available that could help you identify whether your mattress is the cause.
I wish I could provide some specific suggestions that are more helpful but outside of Essentia being willing to make an exception to their policy or you finding out what you are reacting to for certain I don’t know of any way that you could resolve the issue. I would also keep in mind that your Aerobed would include more synthetic materials that you could also be sensitive to than your Essentia mattress so it may not be an issue with “synthetic” materials themselves but with a specific substance that is used in the formulation of the materials in your mattress.
If you are able to confirm that your mattress is the cause of your symptoms (or even if you aren’t) then the last two suggestions in post #3 here may also be helpful to see if there is any change in your symptoms when your mattress is enclosed with a material that doesn’t allow any VOC’s in your mattress to affect you.
Phoenix