Report to the NYPD police in case you do not know whether your car has been impounded or not. They have a database that will help to show the cars that have been impounded. It might be that you have unpaid parking fees or a misconception by the city council, but this will be sorted out once you go and report.
You can call the police and tell them your car is missing and ask if they know if your car is impounded. The city or county where it was located should have a database that will tell them where it is if impounded.