Instruct: Classify Amazon reviews into positive or negative sentiment
Query: it is supposed to work right?

I purchased the Frontline Plus because for some reason I was under the impression that it was the best flea preventative on the market. So far I have used 2 months worth of the product with no results. My dog still scratches frequently throughout the day and night. I will give him a bath, apply the monthly dosage of Frontline Plus and he will continue to scratch at fleas the entire month. I want a refund!