Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Does not work!

First off the shipping took forever, I received the collar, put it on my dog one day. Then all of a sudeen it stopped working. So we got new batteries and it still does not work. And now I am unable to send it back because it is a "hazardous" material!!! I am extremely upset that I wasted 40 DOLLARS for nothing!