DD Motors — No help is given to solve my cng problem

Dear sir/ ma'am,
Namaste 🙏,
I am Kalicharan Verma, bought Maruti Wagon R lxi cng in June 2018 from DD motors Maya Puri, New Delhi.
Got three service done by your workshop. I always requested pick up and drops.
And told about my requirement that my car is not giving mileage on cng fuel please check ! After getting cylinder full around 7.5- 8 kg only mileage I am getting 100-120 km only.
They never bothered about it. And I stopped taking service from dd motor.
Now after getting hydro test After 3 years which is mandatory the mileage has gone down sharply from 100-85 km in full cylinder.
No body outsider is ready to check it as its company's fitted.
Dd motor called me regularly for service for what service they call only to change engin oil, break oil and air filter change and washing the car that's it.
As many times customer Executive called me i asked for the cng tuning service first rest latter but no body is there to help me because you people think nothing wrong will happen to your cng kit fitting but its troubling me from the day one and no one checked on it even making request every time car came for service at dd motor maya Puri service centre.
By default you gave me such unwanted thing which is troubling me till date.
I heard saying people that their Wagon r runs 200-225 km in one time full cylinder and see I bearing with such low quality poor work done by your technicians fitting cng kit in my company fitted kit.
Uf[censored]nbearable now.
Hope you have some answers!
Thank you for never helping After sale
Kalicharan Verma
Wagon R lxi CNG
DL9CAQ2128
JUNE 2018