If the ZOLEO communicator does not respond to your commands you can perform a soft reset. Performing a soft reset forces an immediate reboot of the ZOLEO communicator without deleting any data that might be stored in it (such as messages waiting to be sent, messages waiting to be transferred to your ZOLEO App and your customized settings).
With the device powered off,hold down the Power button for 10 seconds, even after the device powers on. You will hear the device power on, continue to hold the power button during this time and then release after 10 seconds. You'll then hear the device power on again, this indicates the soft reset has completed and you can continue using your ZOLEO communicator.