If you have changed your ID or password, have you followed the steps in this article?
What to do after you change your Apple ID or password - Apple Support. https://support.apple.com/en-us/HT204071
If necessary, contact Apple ID Support.
Apple ID - Official Apple Support. https://support.apple.com/apple-id
Contact Apple for help with Apple ID account security - Apple Support. https://support.apple.com/en-us/HT204169
Get Support https://getsupport.apple.com/. Work through the screens to get a chat option.
https://twitter.com/AppleSupport
Or fill out and submit iTunes Store - Contact Us - Official Apple Support https://support.apple.com/en-euro/itunes-contact The form is for iTunes, but it will get passed to the ID Support section.
From the article below.
Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.
Security and your Apple ID - Apple Support. https://support.apple.com/en-us/HT201303