Waking up miserable every morning. Husband sleeps in chair

When we entered the store to purchase a new matters we were desperate after recently purchasing one from a store that closed and e could not get warranty met. We put our trust in the salesperson and store because the are "Well Named" / big matress chain. We have had the bed 8 months. I did a string test and have divets more than an inch deep. I dread going to bed every night and my husband now sleeps in his recliner. After going to the store to talk to the salesperson, we quickly got a manufacturers warranty # to call. "Passing the buck" I just called the #, sat on hold for 20 minutes and then was automatically disconnected... Can not express my frustration & disappointment right now