Just to clarify, when Microsoft asks you to leave a work organization, your personal account is linked to a work or school tenant in Microsoft Entra ID, even if you did not create one. Sign in at account.microsoft.com then go to https://myaccount.microsoft.com/organizations
and check if any organization is listed. If you see one, select Leave. After you leave, go back to account.microsoft.com/closeaccountand continue the closure steps. If no organization appears or the page does not load, confirm so we can narrow this down.