Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Silicone melted in my oven

First off, I will have to admit that I was stupid enough to buy a flimsy baking sheet that only gets flimsier when heated thus making it impossible to use without a metal baking tray. I burn my fingers every time I use this.Second, the one time I used it without a metal baking tray, it melted in my oven (bottom shelf - bad idea). A hole straight through the sheet and fumes everywhere. I had to throw out everything in the oven and am still slightly paranoid that I may get sick.Third, the times I did successfully bake with the silicone sheets, cookies took longer to bake.I want my money back.