If you can not remember your password, can not access your account on the sign-in page? And follow the instructions to reset it. If you can not remember the email address used with Office 365, you can get a prompt to go to Office.com/setup and enter the original 25-character product key used to activate the office.
On your My Account page, you’ll see a portion of the Microsoft account you used to buy or activate Office, or that you used when you first signed in to My Account.
Select the link Sign in with your other Microsoft account, and then sign in with the correct Microsoft account. If you still have trouble, contact Microsoft Support @ 1-856-514-8666.