In this task, You are given a review of Amazon's food products. Your task is to divide them into two classes: negative or positive, depending on the content of the review.

[EX Q]: I reported a case i bought from amazon missing when it was not delivered to me when amazon said it was. the person i talked to online said that everything was fine and they would send me a new one and not charge me for the first. A month later amazon still charged me again for the phone case i finally received from them. Double price rip off from amazon service department.
[EX A]: negative

[EX Q]: I use my mobile phone constantly throughout the day for work and need headphones to so I can have both hands free. These headphones are amazing, comfortable, and a great buy.
[EX A]: positive

[EX Q]: I guess I mis-understood that this would be a battery back-up for an outlet for a night light or alarm clock. It does nothing, nada, zip zilch. Perhaps it functions as a surge protector, but I doubt it. Why the allegations of battery backup?
[EX A]:
negative