why has my account in itunes and the app store been disabled?

You need to contact Apple support directly as explained in the support document you posted from. Click on the "Contact Apple Support" blue text there to get in touch with Apple Support.

Blocking the charges caused your account to be in bad standing since you still owe the charge that was attempted. The system is set up such that any charges that happen are imitated by you in some form even if you were not aware. Its close to impossible for charges to happen without your direct involvement or of someone with access to your account.

Click on the blue "contact Apple Support" text in the support document you posted from to get in touch with Apple support.

Keatingb8 wrote:

Everytime I go into the App Store a notification saying “Your account has been disable in iTunes and App Store”. I don’t know how to stop it. What do I do?

Follow the steps in the support document at the top of the very post you replied to. There is some issue your account and only Apple Support can sort it out. There is a link in the support document to contact Apple Support for that issue exactly.

Here it is again for convenience: link-> contact Apple Support

Everytime I go into the App Store a notification saying “Your account has been disable in iTunes and App Store”. I don’t know how to stop it. What do I do?