I guess every bike/car owner in Bangalore experiences this.

Points to Note :
1. I am being cheated by these frauds for about 3-4 months now.
2. I visit a petrol pump only when my bike is out of petrol and then fill its tank to full capacity.
3. I have the CITIBANK's Inidan Oil Credit Card and so I prefer going to an Indian Oil outlet.
4. It came to my notice that no matter what petrol pump I go to, these guys always "by accident", fill the tank with Rs.100/200 petrol first then put their display back to zero and fill in the remaining amount of fuel.

The Incident:
I caught them red handed today when they filled in the fuel for Rs.200 and stopped "by accident". Somehow, I managed to stop the guy from filling in any more fuel after that (He was very reluctant though, I had to practically push him away to stop him from filling in any more fuel).
As I checked the tank, there was no petrol in it although, their display said I owe them Rs. 200/- .

There are various complaints on this matter all over the internet.

What is the right approach to tackle this problem?

PS: Any information about the steps to follow to lodge a complain consumer court will be appreciated.