The band are convinced that the N-Dubz singer thought they were too posh, especially because she has made no secret of her underprivileged past.
Fans of the talent competition will see the group dropped by Tulisa, 23, on this weekend's show at the judges' houses.
Three of the boys, Nick Jackson, Rohan Kapoor, and Dan Lipman, all attended St Albans Boys' School in Herts, which has fees of around £13,000-a-year.
A source told British newspaper the Daily Star: 'She gave them the impression she saw them as toffs trying to be street rappers.
'It's like she decided to wage class war.'