Awful Sealy Posturepedic beds at Dial-a-bed

I'm disappointed with Sealy Posturepedic range. After my first purchase, 3 months I to use and the bed began to sag/cave in. Had to take pictures to send as proof. After the bed was replaced, similar issue is happening and the bed is uncomfortable. After sending images and a video I was told to turn the mattress. The mattress is not the type that turns over. So I moved it around and a month later we are still having an uncomfortable sleep. Upon informing Dial-a-bed after the second complaint and following their instructions I'm asked to submit pictures again. As a customer who has comp**** and made a purchase we are unhappy and instead of switching the mattress for a different one or new brand they delay by requesting more pictures. I'm within my rights to request an exchange. Dial-a-bed is not being very helpful.