In this situation you will have to contact your global administrator.
If you are the only global admin then, you cannot login to your tenant without help of Microsoft support team.
There is a dedicated support team who handles these situations.
If you are the only global admin on the account and are blocked entirely, you can reach out to the Azure Data Protection team to restore access. 866-807-5850
Also, for the future, you can create an emergency access account (break glass) in Azure AD. This account will help prevent being accidentally locked out of your Azure Active Directory (Azure AD) organization because you can't sign in for any reason.
Some other support option include;
or creating a ticket through a different account: https://learn.microsoft.com/en-us/microsoft-365/admin/get-help-support?view=o365-worldwide#phone-support
Let me know if you have any further questions on this.
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