The sliders do not move and/or are locked to 0

The sliders themself do work, but your phone's kernel does not support or accept changing the frequency. Possible points of failure:

• sliders locked to 0
  Your device's kernel does not allow the frequency to be read (and not written as well).
• sliders locked to values != 0
  Your device's kernel does allow the frequency to be read, but not to be written

You can check your device's capabilities.