A “green card” is a document issued by the U.S. Citizenship and Immigration Services (USCIS). It provides proof that you are a lawful permanent resident and have authorization to work and live in the U.S.
The U.S. government may deny a green card application for several reasons, such as mistakes on the form, missing documentation, failure to demonstrate eligibility, or insufficient financial resources.
U.S. citizens cannot generally be deported. However, the U.S. government can attempt to revoke citizenship of someone who is a naturalized citizen. This occurs in cases where naturalization involved fraud, such as criminal history or misrepresentation on the application.
If your visa has expired, the best thing to do is contact an immigration attorney as soon as possible. Time is of the essence, and there may be multiple options to have your visa reinstated or apply for a new one.