Instruct: Classify Amazon reviews into positive or negative sentiment
Query: IT DOESN'T WORK! DON'T BUY --

This glass jar replacement doesn't work! You put it together carefully, try to screw the bottom tight (it won't screw tight -- just keeps going around, fill it, try to put the lid on (it won't go on; too big), put it on the blender base, blend it, take it off, and it falls apart and empties onto the floor. Several of us tried it different times and ways, and it won't work!! I returned it for a refund and received the refund, but they refused to refund my $10.00 UPS cost for returning it to them. DON'T BUY IT! --Maurine Fronckowiak, Amherst, NYBlender Jar Bottom Cap for Oster & Osterizer Blenders