Instruct: Classify the given Amazon review into its appropriate rating category
Query: Worked great until it didn't

I liked the unit at first. It was easy to operate and easy to fill. After a week it stopped producing mist. I sent an e-mail to customer service and got no reply ever. I cleaned it several times and it still didn't work. It sat for a few days and I tried it again and it started working again. It quit again after one day. I returned the unit and got a unit from a different company. That unit works fine and keeps on working. The good news is that Amazon makes it so simple and cost free to return a product.