Bests & Worsts Reviews from Amazon

I received first mattress mid-August 2013. After a week it expanded to 8" at one end, almost 9" at the other, with a lump in the middle. It was supposed to be 12". Amazon had no problem shipping a replacement, so my husband and I managed to wrap the partially expanded mattress and have it picked up by UPS at our front door. Amazon paid the return shipping which must have been outrageous, given that the package was huge (54" x 35" by 25"). Replacement arrived beginning of September 2013, and it DID NOT expand either. In fact, one end was less than the other, and the middle had a hump, just like the fist mattress. Explanation I got from the manufacturer Zinus Inc. is that they ever hardly see this problem, and then ONLY IF the mattress has been rolled up a long time. It looks to me like Amazon has some duds in the warehouse and I personally would not "try" another one of these mattresses from them. (And we love Amazon Prime!) I contacted the manufacturer both times. They referred me back to Amazon with the first defective mattress. After the second defective mattress, they fortunately took care of me directly. They asked me to donate the defective mattress to Goodwill and they sent me a free replacement, which arrived 3 days later. They also upgraded the model they sent me, although I am not sure whether that was done intentionally or not. Since I now have a different mattress than what I ordered from Amazon, I am not able to comment on the ultimate quality of this item. I am, however, happy with the replacement mattress that Zinus sent and happy to see a company that stands behind its products. I give Zinus Inc. 5 stars for their customer service.