How can I ipad lock open

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.

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

See the Apple Support article(s) below.

Passcode - If you forgot the passcode for your iPad or your device is disabled.