Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Stained after one use

I recently received this set and upon the look and weight of the set, I was happy. However, upon using the pan once to cook a veggie patty (using spray to keep it from sticking), the bottom and sides of the pan were stained brown. I tried to use the Barkeeper's Friend to remove the stains - this helped a little, but the stains remain. I called Kitchen Aid and told them about this and they said this shouldn't happen. I am not pleased with this product and am going to return it to Amazon.