Have you had injury from the mattress, if so then you can bring a injury action, otherwise this is more of a contracts matter (edited the topics so proper attorneys can see and answer), good luck.
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Have you sought medical treatment?
If you have a dignosed injury, a doctor would need to provide expert testimony at trial regarding causation. That would be expensive so it really depends on what the injury is.
Have you asked for a refund?
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It is likely there is nothing wrong with the mattress given it has been replaced so many times or, if there is something wrong, it is a design defect that will just keep recurring no matter how many times they replace it. You need to try a different mattress. Contact Sleepys corporate office and explain the situation. Tell them you would like to come in and select a comparable new mattress for no further charge. Given the history here, and Sleepys' corporate image concerns, they might just do it, even if you're not entitled to it. Also, on a different note, if you wish to sue Sleepys for personal injury, please note, in NY, there is 3 year statute of limitations for doing so.
I don't understand why you would keep getting the same mattress 6 times as it obviously does not perform as expected after first few times. Tell Sleepy's the specs (detailed) you need for the back issue problem and have them do the research to find you an even better (and different) mattress given the aggravation you have gone through. If they are not willing to do so then sue them for the defective product and ask for your money back so you can go elsewhere to obtain what you need health-wise.
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