A day before my oat ceremony, I got a call from a field officer saying I should not attend the ceremony. He said they will send me a letter, explaining why, which they did. It turns out that though I was married for 4 years to my ex wife, she divorced me six month prior to my permanent resident card arriving in the mail (at the time of divorce i wasnt aware she had divorcec me) So at the time my card arrived in the mail I was no longer married, though I wasn't aware. I have had my green card for seven years now and at a risk of loosing it. Married in 2001, filed residency 2001, I had to file an I-601 waiver in 2004, July 2005 she had divorced me, February of 2006 my permanent resident card was granted. Now i am told my PR card was granted in error, 7 years later. What can I do?