Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Doesn't work on my Smart Boss

Have had my vacuum for about 5 years and it's still good as new. I completely forgot that I had ordered these once before until I installed the new one and the brush roll came to a halt on my oriental rug, just like last time. For some reason, there is no height adjustment I can make to keep it spinning AND cleaning. I can raise it high enough to spin and it doesn't pick up debris. When first installed, I also have trouble with the brush roll continuing to spin when in the upright locked position and, consequently, burned brush lines into my non-wool oriental rugs when I didn't notice it hadn't stopped spinning. So for me, 1 star!