Instruct: Classify Amazon reviews into positive or negative sentiment
Query: iAudio U3

I trust iAudio's quality on its products since I own an U2, and that's why I got the U3 for my sister's birthday. However, when I received the refurbished U3, the display is barely readable. Fortunately, Cowon's prompt customer service and repair fix the problem within two days. Now the player works great.