My suggestion is to first check if the microcontroller is alive. For example, try to upload a firmware, or even simply run the following command (with USB cable plugged in):
avrdude -c usbtiny -p m328p
and see if there is any response. If the controller doesn’t respond to firmware update, or to the above command, it’s likely that the microcontorller is damaged. If you can’t figure out, send an email to [email protected] and we can follow up from there.