National Customer Service Center at 1-800-375-5283

Rental car is fine. They don't ask you to show them your car. I did not call the border office. I called
National Customer Service Center at 1-800-375-5283. You may try to call this #, and ask to transfer to the immigration officer. But I think they are stricter than the border office (Seatle or Niagara Falls).

Good luck