TVS Service center Cochin

I went for my regular service for 60,000 at TVS cochin.The service engineer asked me if i had any complaints with the car.I told him all is well,except for some screeching sound while i press on the breaks ,more in mornings and would fade off later.He said we need to change the coolant and a belt near the radiator and would look into everything.I was called in the evening, citing the car was ready.I asked about the break issue and he said there's no problem with it at all and was told to pay a bill for 8000/- for oil change ,oil filter,fuel filter and air filter.....However,i drove the car home to realize that the car never looked like it was ever serviced.I checked the oil and found that it was murky and jet black,and was convinced that it was not changed and i was billed for it.I had to to go to Trichur the next day.While driving i noticed the power had dropped down drastically and idling was difficult ,and noticed thick black smoke emanating from the exhaust pipe.I called up the TVS guys and queried about the horrible experience.I was told EGR valve needed cleaning up.I asked any EGR valve problems cannot evolve suddenly,it usually shows symptoms earlier.I noticed also that the setting had gone to Zero,like mileage.I also noticed my car was never moved out of the facility for testing too because the odometer reading was the same as it was on delivery.I went there for the so called EGR valve cleaning and was charged another 3000/- for it.However, i noticed no great benefits at all apart from a slight reduction in black smoke.After consulting so many experts on this i was told that my original EGR valve could have been stolen and a defective one placed rather.After that i noticed oil leakage from the intercooler area too.I feel these guys are inducing new problems intentionally.
I had told the service engineer my discontent about no oil being changed and additional problems propping up.I'm actively pursing to file a criminal case against the service engineer and manger for theft of parts and intentionally damaging my vehicle to cull more money