Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Just doesn't work

I bought this product on Consumer Reports review. It took some time to figure out how to get it setup (terrible documentation). Then, no heart rate is displayed. I tried all the suggested remedies except buying a new battery (are they serious?). I returned that one and got a replacement. Same problem.I read these reviews and found that a hairy chest is a problem and even after getting past that, the product sucks for a lot of reviewers. So I'm returning the second watch as well. The product must be costing Amazon a fortune.