Our I 171-H is on it's way!!!!

Here's the deal. I received an email a couple of weeks ago from the CIS office wanting our physical address to send out our I171-H, well we waiting then we received a letter stating that the State Dept. had received our approval and our petition has been given a case number. Still we still didn't received our I171-H. We got an email from the CIS office and it said that our I171-H had been returned to their office stating return to sender...The problem was they had sent it to our physical address and we get our mail at a P.O. Box... I emailed them back and she said that they would send it out with a cover sheet with our P.O. Box.... So that's where we are now... Once we get the letter and send it to Kate we are on the Waitlist!!! Praise God!!!