Instruct: Classify the given review into positive or negative sentiment.
Query: Warped and Warped again

Out of the box the pan I had warped after the first use. If you have a glass top, or otherwise completely flat cooktop stay away from this pan.I contacted Calphalon and was sent a replacement which took approx 2 months. When I received the replacement I put approx. 2 cups of water in it and began to heat it on medium high heat and had the same result. It had a terribly warped bottom and is what I would consider to be unusableI do have other pieces of cookware from them that do not exhibit this behavior. I am again contacting Caphalon to replace the pan a second time however since I have had two pans now with the same problem I have little faith that a third replacement would be better.