how to disabled it

How to disable what ?

If you mean that your iTunes account is disabled then you might be able to re-enable it via this page : http://appleid.apple.com, then 'reset your password'

You might then need to log out of your account on your iPad by tapping on your id in Settings > iTunes & App Store (Settings > Store on iOS 5 and below) and then log back in so as to 'refresh' the account on it.

If that doesn't fix it then you might need to contact iTunes Support : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page

You will need to connect your iPad to your computer's iTunes and you should be able to reset the iPad : http://support.apple.com/kb/HT1212 - you can then restore/resync your content to it