BAD SERVICE

I REGRET EVER BUYING A CAR FROM MAHINDRA!!! Last month I took the car for service and paid. No fault report, they just took payment, noticed the lights dim and a noise from engine getting louder and louder as days went by. Booked it again to have it checked and to my surprise got a huge quotation of R28 408.60 and the explanation is we didn't check the car we serviced the car changed oil. What is service? I've had about 3 to 4 cars in my life and never had this baaaad service and their charges are disgusting 8X LABOR CHARGE on one job - no quotation but didn't even open the car just gave diagnosis, like REALLY!!! Why are they robbing people? Why are they doing half jobs and injecting more problems in the cars so that you come back and pay? Why are the dealers in Cape Town doing this to us? I WANT THEM TO FIX MY CAR ITS JUST OVER A YEAR OLD FOR THE REPAIRS THEY CLAIM WHICH THEY DIDN'T SEE NOR DIAGNOSE WHEN THEY WERE SERVICING THE CAR LESS THAN A MONTH AGO, 15TH SEPT TO BE EXACT.