Poor Customer Service Following Mattress Purchase

I purchased a mattress (Restonic - Plush). After sleeping on it for less than two weeks, a noticeable slope developed where I slept and that same area felt "mushy". It was very uncomfortable. In order to get some comfort, I have to, each night, move around the bed to find a leveled and firmer place to sleep. I invested more money into this one for assured comfort and longevity - more than I ever have for any mattress. Instead, I have found it to be the most uncomfortable mattress I've ever owned! My back and shoulders hurt as I wake up with an ache from it during the night! I can sleep at my parents house or on a sofa and not have that to occur! Sometimes I regret having to go to my bed at night because of the pain/discomfort caused by this mattress! When I contacted the store after this experience, I was told to speak with their customer service. I did, and not only did I tell the rep of the discomfort, but I also mentioned about a visual slit underneath the mattress that I'd previously mentioned to the salesperson following purchase. I spoke to two different reps at different times. Both gave me the strong impression that their job was to prevent me from getting satisfaction of the mattress being replaced, even considering the defects! One of them said I signed a paper on the delivery date and did not mention the discrepancy. The other rep said I was suppose to flip the mattress each week! I was appauled and let him know that. He then changed it to a two week flip or likewise, changing bottom to top every week or two! He said, otherwise I would experience what I complained about the mattress. I told my salesperson that Miskelly's reps and sales personnel are oh, so courteous, obliging and seemingly honest when trying to make a sale, but no longer exhibit the same behavior when you need assistance post sale!