Body impressions make for hard nights sleep

This mattress was supposed to be something great for mine and my husbands back. First off it is way too hard. After about 30 days our body impressions were molded into the mattress on our sides, leaving a huge lump near the middle where we don't sleep. It gets so warm evef on the coldest day my husband sweats so much, hd has to kick off ghe sheets. I'd love to just get up and buy a new mattress all together. Not satisfied with this serta mattress.