Sleepy's Warranty Void Nationwide

My grand parents bought a mattress here a little over a year ago.  The sales person did not go over proper support on their bed for the Mattress they were buying and after a year the mattress started to sag.  The delivery men also mentioned nothing about support voiding the warranty,not to mention they didn't receive any warranty info at the time of delivery, nor is it on their sales slip. Sleepy's denied their claim, and has refused to do anything to help them or make it right other than offer a "steep discount" which they wouldn't say what it was.  Knowing how their pricing works with 5 pricing levels (1, price on the bed. 2 first price below that to keep you in the store, 3 another discount to get you to buy today, 4 bigger discount to stop customers from comparison shopping, 5 the lowest price they can offer to still make money and make sales during slow periods), unless discount is in the 80% range they are still making money.  Very disappointing to take advantage of two 80 year old people.