There is no option but to trust them.. then prepare and answer to your best.. if you doubt them, you will always have the feeling that no matter how hard I try I'll fail. And if the checking procedure is correct, you will fail because of your mentality, as you didn't prepare well.
You damn sure you should have passed?? Maybe you thought you wrote good answers, but they were not as per the requirements, compare your answers with the suggested.
Now in CA, don't expect or intend to pass by the borderline, you gotta be thorough, prepare with an intention of getting exemption i.e. 60 marks.. or, atleast 50 marks in each subject.. don't intend to somehow manage a 40.. it's a gamble.
As a saying goes, "Shoot for the Moon. Even If You Miss, You'll Land among the Stars."
It's just your thinking that there you were the only punjabi there, there could have been more... The urban legend I have at my place is that ICAI gives preferences to the north-western people, esp. the Gujaratis and the Rajasthanis.. Now that's funny as I know a lot of n-w people who still fail and I also know a lot of people who are not from these regions yet pass..
If you don't trust the Institute, I say leave the course.. Your way or the highway.. or, why don't you experiment changing centres? ;)