@OP - Did u check pulses in injectors while cranking?? If pulses are not coming then definitely FI Fuse is gone. U can check FI Fuse on Fuse Box and replace it.
I think u r not that tech to check the pulses urself but atleast u can check FI fuse in the fuse box (check the top of the box to locate the fuel injectors Fuse).
If FI fuse is okay then there can be issue of fuel pump. I think its better to visit a good mechanic - better not to test anything by urself.
Edited: I was thinking, u r just facing issue in starting the car but after reading ur post again, I think there can be issue of CNG switch/Wiring. Why not to show it to a CNG guy?
All the best.