Instruct: Classify the given review into positive or negative sentiment.
Query: Weak product worse customer service

I bought one of these yesterday and returned it the same day. It just didn't work. All it did was hum.I own a Hydrofloss brand oral irrigator which I have used for several years. It's loud, but never a problem. I needed a second unit for travel and couldn't find the Hydrofloss locally, so I went to a large local department store in NYC and on the recommendation of the salesperson, I bought the Water Pik Ultra.The Water Pik never left the starting gate. I thought I might get help from customer service at Water Pik. That was an even bigger laugh. Called the number in the instructions mid-afternoon EST on a Friday, no answer in 100 rings. Called three different times, rang 100 times: no answer.Bottom line: no quality control, no customer service. Buy at your own risk.