Hi vmc,
You have certainly had some unfortunate experiences.
If you are looking for a new mattress then the first place to start your research is the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones.
Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on all the parts of your personal value equation that are most important to you.
There are certainly some very reliable and knowledgeable retailers or manufacturers in most areas of Canada and the US. One of the most effective “shortcuts” when you are looking for a new mattress that can help cut through much of the confusion and uncertainty that can be involved is to focus first on finding and dealing with knowledgeable and experienced retailers and/or manufacturers that have your best interests at heart (and aren’t just interested in selling you anything that they can convince you to buy). These are the ones that already know what you would otherwise need to learn and understand the importance of choosing a mattress that is a good “match” for you and are transparent about the type, quality, and durability of the materials inside any mattress that you are considering. They can provide you with the type of information and guidance that can help you make the best possible choice. Who you choose to deal with can be one of the most important parts of a successful mattress purchase.
It sounds like you are in Canada and if you let me know your city or postal code I’d be happy to let you know about any of the better options or possibilities I’m aware of in your area.
Phoenix