Resolved Sequential kit Problem with CNG Light Blinking in Maruti Wagon R

Hi
I have wagon R lxi 2011 k series retrofit with sequential Tomasseto CNG kit from a authorized Centre
around 15 months back.
First 12 months were good no problem at all around 20,000 km done. But since 3 months there has been a jump from CNG to petrol with the CNG light keeps blinking in the switch.This occurs specifically in city traffic. And problem sometimes occurs several times a day and sometimes no problem for 3-4 days straight.
Several authorized centers failed to diagnose the problem though on running diagnostic with laptop it shows faulty injectors, Tried with changing the injectors of cng but the problem remains the same and even with new compatible injectors laptop diagnostics shows faulty injectors.
Every other CNG fittment center tells a different fault.
One wants to change injectors which I agreed but didn't resolve the problem.
Second one says its faulty ecm, third one says its fault of plug in reducer, third one says its timing advancer failure.
No one gives a guaranteed solution.
Please help