HELP:Xbox 360: Mission 18 : out of ashes (GLITCH : STUCK IN ELEVATOR )

After the part where you are in a tank, you have to enter a building and take the elevator that normally brings you upstairs. I call the elevator, elevator comes down and when i enter and walk up to the buttons in the elevator, nothing happens, the doors don't close and can't move on. Normally the elevator should automatically bring me upstairs but nothing happens. Now i can't even finish the campaign :< . I already restarted checkpoint, mission but nothing helped.