Your Apple ID account becomes disabled for one of two reasons. Either
1) You tried to enter the wrong password or wrong security answers too many times - in that case, head over to https://iforgot.apple.com to get started toward recovering your account
or
2) You owe the iTunes Store money or there is a problem with your iTunes account - in that case, head over to iTunes - Official Apple Support for assistance or fill out this form: https://www.apple.com/emea/support/itunes/contact.html