As 3,000 Justin Bieber fans massed at Long Island’s Roosevelt Field mall on Nov. 20, the teen heartthrob’s manager refused for 2½ hours to call off the dangerously overcrowded event, authorities said yesterday.

Warned that he would be arrested if he didn’t use Twitter to alert fans that the appearance was canceled, Scott “Scooter” Braun brashly advised cops to spell his name correctly on the arrest warrant.

Braun, 28, of Atlanta, was released on his own recognizance yesterday after appearing in Hempstead District Court.

Braun claims he was unable to use Twitter to announce the cancellation because he had no computer access.

But Braun told a colleague he was “playing dumb,” Nassau prosecutors charge.