My NUMKEY is not responding - First thing you can do is double check that the NUMKEY is set to the proper mode, either USB or Bluetooth and that it's not off.  There is a toggle switch on the RIGHT SIDE of the NUMKEY.  

My NUMKEY isn't typing any numbers - Be sure to toggle numlock by pressing FN + NL(ESC) key. Also try setting the NUMKEY to win mode for maximum compatibility by pressing FN+win (/) key 

My NUMKEY "CLEAR" key doesn't work - For mac users, try setting the NUMKEY to win mode by pressing FN+win (/) key.  This will make the "CLEAR" key behave as a "DEL" key in mac.