Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Bad Machine

Purchased this unit from the merchant MoreQualityLessMoney and Fullfilled by Amazon. When we plugged in the unit, it emitted a foul odor that caused a pretty severe allergic reaction. Since the air purifier was supposed to clean the air and not make it unbreathable - this was not a desirable result. I am afraid that the unit's filter became tainted prior to shipment or was manufactured improperly. I cannot recommend this product and do not think I would be willing to gamble on getting a good unit. I think I'll write this off as a failed experiment.The only positive thing about this experience is the great customer service provided by Amazon. When I contacted Amazon, my customer service rep immediately e-mailed us a return authorization and pre-paid UPS label to return the Healthmate. I have been shopping with Amazon for a long time and they have always given me superior customer service.