Hi. To me it kinda sounds like an unplugged connector to the gasoline tank or in the change over system.
I was just thinking that lots of government agencies used cng vehicles especially when they started making them. Maybe if you know where a public works repair garage is or something like that you could ask someone there if they know anything.
There are specific Ford dealers that were trained in CNG systems. Since you are in Canada, I dont know if Ford had many there. Usually they were delivering dealers to fleets. For example, Pacific Ford in Long Beach, because the city of Long Beach has a huge CNG fleet of Crown Vic police cars.