Oh dear, sorry to hear. Does the push button work to scroll through the lcd menu? Can you shut down the unit via the admin menu when logged into local emoncms?
This is the same with the emonTx, emonTH and the emonPi. From the FAQ:
Q: My emonTx / emonTH / emonPi won’t read the new sensor that I just plugged in. How do I fix it? A:
Power down and power up again.
Almost all of the sensors attached to an emon sensor node (emonPi, emonTx, emonTH) need to be present at power-up, else they will be ignored.
The sensors are handled by the Atmel 328P inside the same enclosure as - but independent of - the Raspberry Pi. So rebooting only the Raspberry Pi will not resolve the issue. Powering off, then on again, resets the 328.