Hi @Nandhini Velu · Welcome to QnA platform and thank you for reaching out.
The recommendation is to always keep break-glass admin account, by excluding one or more global admins so that you can revert the settings. However, if you forgot to keep a breakglass account, the only option is to open a support ticket to get Microsoft Data Protection team engaged for this issue. If you are unable to sign into your tenant, you can use any other tenant or signup for a new one to open a support ticket.
After providing required information and evidence to prove the company ownership on the subscription, they can help you with providing admin access to your tenant.
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