If the system is still under warranty, you can contact Polycom for a warranty repair.
If it is not under warranty, then try a reset:
There should be a reset button somewhere on the unit. Hold it down, and hard cycle the power. Keep holding the reset button down. Keep holding for as long a time as possible, several minutes, to ensure it resets.
Let me know if that works?
If the reset or restore didn't work then the phone will require a repair.
Is it still under warranty? If so, you can return it to Polycom for a warranty repair.