Hi Singh,
Sorry to hear that you application got rejected. I have gone through with the same situation. My application was also rejected by CIC. Immigration officer called my employer to verify my job duties and pay, but my manager was failed to describe all the duties which I have done, (He described 80% duties but could not described all of them because he was nervous at that time) just because of this reason they refused my file but I challenged their decision in the court and at I won the case and got my PR.
This is just a basic information what to do If your file gets rejected. After talking with my lawyer I found out you can not reopen your file, you can send the clarification letter but they do not accept it because your file is already closed. I think the only way is, to challenge the decision in the court, but for that you have to apply for Judicial Review within 14 days of refusal letter. This process is complex, you need a good lawyer to represent you in the court. And if you want to know complete process, let me know and I would give you all the information. Act fast you do not have much time.
