If you need a mattress, try shopping at a store that not only has the type you need, but offers a guarantee that is clearly stated and explained before you part with you money. I knew I had followed my advice.
After delivery, I believe my mattress was flawed and I wanted to exchange it for another. I followed the small print rules. After 3 months, nothing has been resolved. They seem to have an explanation, but not a solution. Once they have your money, you hope you made the right decision and are not faced with a manufacturing problem with your purchase.