Maruti Suzuki India — the huge amount they looted for servicing

I purchased my maruti swift vehicle on april 2016. Then my free service ended in 10000 km. After that i got cal from pratham motors and they updated that my next paid service is on 15000 km. Then 2017 july i gave vehicle to servicing, this time they changed the oil and filled the syntetic oil and total service cost is 3600. After that again i got a cal and they updated like your next service is on 20000km, this is happening after the 6 months of first paid service and i agreed. This time they told the service cost will come upto 7600 approximately. Then in between the servicing they called me and told taht they are going to do some additional things like ac cleaning and painting. This will cost around 3000 but you will get it for 2000. Then i started shouting and asked why am paying these huge amount of money for servicing, then suddenly they reduced the service charge to 6700. And i dont have any option so i agreed. After that i calculated and realised that total 11000 rupees i spend for servicing in one year. And i again realised that this 15000 km servicing is not at all required.in this service they changed the oil to synthetic and again they changed the oil in 2018 feb service.in my understanding synthetic oil will last upto 10000km. But here they chaged after 5000 km itself. One more thing the reason why people purchasing maruti vehicles are mainly because of its low maintenance cost. Here i spend almost 11k rupees within 1 year time period. Usually in my awareness the diesel vehicles itself will not cost these much. And question here is, this service stations are really meant for customers or only for the agencies like pratham. Am going to write this bitter experience in social media very soon. And if am not getting any proper response from your side i will defnitely go to consumer court. There are lot of other things to mention like the parts they changed and the quality of the servicing and all. I dont want discuss all this toghether. First i want to get a proper answer for this question and after that i will take the other issue. Actually am feeling like looted here.