Unlock iCloud

See these articles https://support.apple.com/en-in/HT201354

https://support.apple.com/en-us/HT201487

You can change the password using this method .

Go to iforgot.apple.com and enter your Apple ID in the field , click on continue , in the next pop up window check the box of I need to reset my security questions , click on forgot password then check the box of answer security questions and click on continue .

Enter your month/date/year and click on continue , the questions will be displayed you have to fill correct answers for them , click on continue in the next pop up window enter new password and confirm it , finally click on reset password .

Go to iforgot.apple.com , type your Apple ID address in the field and click on continue check the box of I need to reset my password , click on continue .

Check the box of get an email and click on continue .

Then open your rescue mail account with web browser ( server account ) , open mail in the inbox > click on link reset password > two fields will be shown .

( a ) new password …..

( b ) verify password ….

Enter the credentials , and click on reset password , the password is changed .

Go to https://iforgot.apple.com to retrieve yourI ID and reset your password.