Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
There are two reasons for this problem. First is that if someone has tried to login to your Apple ID with too many incorrect passwords then Apple will disable it to protect the information of your account.
To enable it back, you have to reset the password. You can reset it from here --> https://iforgot.apple.com/
Go to the above website. Use the "Get an Email" method to reset the Apple ID. Apple will send the reset instructions to the recovery email you setup with your Apple ID.
If that didn't work, then reset again and this time use the "Answer Security Questions" and answer the security questions there to reset your account. After resetting the account, you will be able to download using it.
If resetting the password *****'t work, then here comes the second reason. If Apple has noticed any issues with your card or payment information like report of fraudulent charges, refunds etc they will disable the App Store part of your Apple ID. You will still be able to sign in to your Apple ID, change payment details, password ***** but you will not be able to purchase or download or update your apps. Because they limit the App store part of the ID.
So all you have to do is call iTunes directly and ask them to reactivate the account. Only they can access the database and enable the account for you.
To contact iTunes Support, goto this link --> https://www.apple.com/support/itunes/contact/
Click Contact Support at the bottom, click Contact iTunes Store Support at right.
Click Account Management. Click Apple ID has been disabled alert
Click Schedule a Call and they will call you Or you can call them from there. Then you will have to answer some security questions and they will enable the account with in a few minutes.
If you have any questions or would like any additional information, please don't hesitate to ask.