Defective Mattress

We've had this mattress for four years and pretty much since the beginning have noticed a "hole" in one particular area of the mattress. I rotated the mattress regularly with the hopes of it evening out. The hole is not visible and the warranty requires a 3/4" or more visible depression, so I hesitated to file a warranty claim. After four years I decided that I would try because whenever I rotate the mattress to where the hole is on my side, my back goes out. For warranty claims, Pure Talalay Bliss requires pictures of the foundation and the mattress showing the measurements of the depressions...no easy task as they want the mattress photos taken with the mattress off of the foundation which meant moving an extremely heavy mattress out of my bedroom, down the hall and into my living room. As I expected, depressions measured just slightly over 1/2" and the hole was not visible. Pure Talalay Bliss denied my warranty claim based on the fact that the depressions were under 3/4". I'm left with an expensive, defective mattress and no recourse available.