My wife’s F1 visa expired on 9/09. She applied for a change of status (COS) from F1 to H4 dependent of my H1b in 9/09 before F1 expired. My H1b started on 10/09. While her COS was pending, we traveled to our home country. I got my H1b and she got H4 visas in our home country through the US consulate. We both entered the US with the new visa. After we came back to US, the COS application requested additional docs. We sent the docs along with a note saying that she had already got an H4 visa from the US consulate. We then received a letter saying her COS was denied because she left US during application. The letter also ask her to leave within 15 days. Is it legal for her to keep staying in the US?