I guess you are applying for Canada immigration.
It seems that CA INS is reluctant to response to
your any enquery, no matter how many times you have
made such enqueries.
At this point, you have no choice bug wait.
I know one of my friend, after he sent out his application, he never received his first letter.
After about one year, when all of us thought that
his case was lost, he received his second letter.
Good luck!