Work Performed: Responded to no heat call for natural gas furnace. Upon arrival, found furnace and water heater both off in error state. Assumed something was off with the gas supply and found the gas meter locked. Also noticed the Pressure relief valve on the water heater was slowly dripping. Inspected gas system and found the exterior gas meter locked off by Enbridge due to a billing issue with a previous tenant. Advised client to contact Enbridge to have gas service restored. Explained that the pressure relief valve drip may be related to the rapid temperature drop from the gas shutoff. Recommended monitoring after gas is restored. Results: - No heat due to gas service being disconnected. - No active equipment diagnosis performed due to gas being off. - Recommended scheduling a full maintenance once gas service is restored on furnace , it show signs that maintenance is due.