iCloud says "Password is wrong", but I think it's correct iCloud says "Password is wrong", but I think it's correct. How should I proceed?
Head over to https://iforgot.apple.com/ and follow the procedure there, including contacting Apple Support if everything else fails.

When an account gets locked - even the correct password won’t work so talking to someone that can help you in a locked account situation is the best strategy since they will also be sure you’ve used the correct troubleshooting steps like checking system date, restarting the device, trying another network based on what their dashboard shows for your account.