Instruct: Classify the given review into positive or negative sentiment.
Query: not working

Bought this to keep soup warm for lunch. Does not keep soup warm for even four hours. I have tried to find out how to get replacement, but can't figure out a contact number. I contacted manufacturer but they won't help due to having it for only two weeks. They say seller must replace. Urgh!!!Follow up. My thermos was replace by Amazon and worked great for 3 months, and then suddenly doesn't keep anything even warm.