The standard answer to the phone LED being off is at
http://obihai.com/faq/Troubleshooting-sec/My-Phone-LED-is-not-onHowever I wonder what was behind you saying ".... and even plugged the phone directly into the phone port of the Obi100 ..". Did you ever have the house wiring plugged into the OBi's phone port? If yes and there was another provider (telco POTS line or cable TV phone service) connected to the house wiring, the voltage on it may have killed your OBi's phone port.