how to unlock a disabled device

See 'Your account has been disabled in the App Store and iTunes' https://support.apple.com/en-us/HT208856. This link says: "There might be a problem with the payment method that you have on file. When you see the message, don't try to edit any of your account information. Instead, contact Apple Support for help.”

Use the Apple recommended support link above first.

You can also Get a call from Apple support to help solve your problem https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

And you can use Apple Support Twitter https://twitter.com/AppleSupport

And, if necessary, go here to contact iTunes worldwide support via text or chat https://support.apple.com/choose-country-region/itunes After choosing your country, see the heading, Tell us how we can help.

See: If you forgot the passcode on your iPad, or your iPad is disabled - Apple Support