My App Store has been disabled. How do I fix it?

You’ll need to contact Apple—we’re other users and not folks that work for Apple, and we can’t access your Apple ID, purchases, or related data—to determine what might have triggered this, and to resolve whatever happened.

The official answer from the official Apple folks:

If you see a message that says 'Your account has been disabled in the App Store and iTunes' - Apple Support

See the link in the article, or use the Contact Support link in the upper right.