Duplicate iCloud accounts without MacBook access

Hello,

With the old account you are trying to access then delete, do you know if your old MacBook was the only trusted device you were signed into that account with? Mac’s, iPhone’s, iPad’s, iPod touch’s, and Apple Watch’s can all be trusted devices. If you have one of those, that is already signed in to the old account, charge it and turn it on. After the device is on it should be able to receive a code for you.

If you don’t have another device that used your old account, hopefully you added a trusted phone number which you can still receive text messages or calls with.

Get a verification code and sign in with two-factor authentication - Apple Support

"Get a text or phone call

If you don’t have a trusted device handy, you can have a verification code sent to your trusted phone number as a text message or phone call.

1. Select “Didn’t Get a Code?” on the sign in screen.
2. Choose to have the code sent to your trusted phone number.
3. You’ll get a text message or phone call from Apple with your verification code. This text message might include an additional domain validation line. This line includes the @ symbol, the website name, and your code (for example: @icloud.com #123456 %apple.com)."

If that is also not possible you might be left with using the account recovery process.

How to use account recovery when you can’t reset your Apple Account password - Apple Support

"What is account recovery?

Account recovery is a process designed to get you back into your Apple Account when you don’t have enough information to reset your password. For security reasons, it might take several days or longer before you can use your account again. We know this delay is inconvenient, but it’s important so that we can keep your account and information safe.

Before you start the account recovery waiting period, try to reset your password on a trusted device.

Use account recovery only as a last resort when you can’t sign in or reset your Apple Account password any other way.

• If you don’t know which email address or phone number you use with Apple Account, try different email addresses or phone numbers. You can sign in and reset your password with any email addresses or phone numbers on file in your Apple Account.
• If you don’t have a trusted device, you can reset your password using the Apple Support app on a family member’s iPhone or iPad. You can also visit an Apple Store and ask to use a device on site.
• If you set up an account recovery contact, they can also help you reset your password."

I hope this helps.

Based on your thought that the account was used on a device issued for education it is possible that the account is actually a “Managed Apple Account.” in education they are created for students by education institutions using Apple School Manager. If the account you are attempting to access is something like lastname.firstname@icloud.com(or similar) and you don’t remember creating it, was likely created by the school you who issued you the MacBook.

If that’s the case you would need to contact the school to request they deactivate and delete the account. In the unlikely scenario that they would purposely continue providing the iCloud Drive subscription for former students, you would need to contact them as the Apple Account is technically owed by the institution. Password rules are controlled by them as well as a long terms code giving users access to the account on iCloud.com.

Use Managed Apple Accounts in Apple School Manager - Apple Support

Create or reset user passwords in Apple School Manager - Apple Support

Beyond that, attempting the account recovery option from my previous reply is the only other thing I can think of to gain access.