Maruti Suzuki India — faulty ciaz car

Address:

Chennai, Tamil Nadu, 600043

I purchased ciaz alpha car from pillai and sons chennai and service been given to popular motors porur chennai, they have changed my car parts, like 1. Power button knobs for windows, windshield wiper, car seats, ac controller knob, wheels, car milage 9km/liter instead of 21km promised by maruti. I gave my car for service 4 apart form 3 regular free service with running repair. They have not taken any intiative till date
Even higher authorities are playing game with showroomanagaer etc. Doing water wash and returning my car backhand lot fights with verbally nogo. Am unable to drive me car. Any further complaint has to be made to this issue or planning to go legally with consumer complaint.