Can anyone please tell me something about how to challenge/claim for any post in fpsc? Please read below scenario.

1. From Sindh Rural only 3 candidates were short listed for single post (sindh rural).
2. at the time of interview only 2 candidates (including me) were present there for interview, and in that list (on which we sign for attendance) only 2 candidate's names were written (me and the other guy).
3. But few days before fpsc has Recommended a guy which was not in interview at that time. When I asked to assistant about that one, he replied that I don't know I have got only this list.
4. I was sure that I will be selected because none of the question in interview was wrong by me, not I hesitated there and neither I was nervous.

Friends please suggest me what should I do. I am waiting for your responses.