Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Stopped working =(

I bought this for my outdoor cat to keep her warm at night. It was placed in a cat house with minimal exposure to outside. The first night I used it, it worked very well and the cat slept on it. I plugged it in on the next cold night and it would not heat up...I may just have a defective product (as this product has many great reviews) but I was very disappointed. I am now looking at another brand heating pad for my cat.