One option is for you to try to login with the same admin account and hit the "Forgot password" option and using an alternate email to reset the admin password. If that isn't possible for whatever reason, then, you can try contacting the Office sales support team and provide verification details like the credit card number associated with the purchase, contract information etc. and verify that you're the one who owns the Office tenant. Once this identity is successfully, they should be able to help you recover your account with a way to reset the password. Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.
Gain Access to account
The Admin for our clarity account has left the business, how can we regain access to the account as we currently can't do anything with it and the scripts are effecting our site speed?