Check the floor setting is set to 'carpet'
Your unplugged cleaner is suitable for both hard floors and carpets. You can change the setting with the switch at the top of the handle. When you select the floor setting the brushes will not spin.
Check the setting you have chosen if you notice that the brushes are not spinning. Choose the carpet setting to make the brush roll spin.
Always disconnect your appliance from the mains before you start examining it!