Dear Stephannie, My name is Ben. I am the Retail Manager at OM. I have no record of any complaint of a Restonic mattress sinking in the middle. Our mattresses come with a 10-year warranty, if you have such a complaint please do send a private message with your order number and I will attend to your complaint accordingly. If you have a grievance with another person in this forum do take it up with the administrators. In fact, I had to complain to the administrators about your earlier post about my company and they investigated the complaint and you did not back up your complaint so they kindly remove the thread. Cheers, Ben