Hello @Satya Rekapalli , in order to re-gain acces to your Azure AD B2C tenant as a Global Admin after being locked out due to MFA you will need to reach one of our business support numbers. In a future, to avoid facing the same issue consisder creating emergency access accounts.
Let us know if you need additional assistance. If the answer was helpful, please accept it and rate it so that others facing a similar issue can easily find a solution.