Hyundai fluidic verna giving pick-up problem

I purchased new hyundai fludic verna (petrol) in juny 2011 from sunrise hyundai, I.P. Extension, delhi-110092. During MID-april 012, it started giving pick up problem. Initially I DID not take it seriously. However, after sometime, I left the car at the service station. When I got the delivery of the car, they said the problem has been rectified. However, the problem was still persisting. Therefore, I left the car again with the service centre after 5-6 days. The car remained with the dealer for about 2 days and at the time of delivery they informed me that the problem was due to the fact that I was using premium petrol in my car and they advised me to run the car on normal petrol. I followed their advice but to my shock and horror, now not only the pick-up problem remained, the average of my car went down to only -7.5 kms. Per litre. I again went to the service station. After keeping the car at the service station for about 2 days, they delivered the car assuring me that they have checked everything and the car is running fine now. They even charged me rs. 00/- By stating that they have used the petrol of rs. 00/- For checking my car. However, the problem still remains there and it is very risky driving the car as suddenly in the middle of the road, you find that the car is not moving. The problem is worse in case of a traffic jam. The car is giving an average of only -7.5 km per litre (that too without ac). I have called up the customer care number for about 5-6 times and they have also giving me complaint no. 1- 4085 but they have taken any action on my complaint. The customer care executives have been trained to tell only few lines when you call them to know the status of complaint. They are good for nothing and in my opinion, these type of customer care service executive are sheer waste of your time and effort as instead of caring for the customer,they are harrasing the cusotmers by not providing the customers with any solution. They do not even give you the contact details of some higher ranking person who could do something concrete to resolve the issue. I am dissaponted with the manner in which hyundai people are acting and would like to advise all who are planning to buy hyundai verna fluidic to reconsider their decision in the light of my experience.