
Hi there, this is Marc. Thanks for reaching out the community.
The error you are seeing happens when the system does not recognize the phone number or when there is no other verification option available. In this case, the best steps are to first wait 24 hours before trying again, since too many attempts can trigger temporary blocks. You can also use the Sign-in Helper tool at https://support.microsoft.com/en-us/account-billing/i-can-t-sign-in-to-my-microsoft-account-475c9b5c-8c25-49f1-9c2d-c64b7072e735 to go through guided recovery steps.
If that does not work, submit the Account Reinstatement form at https://www.microsoft.com/concern/AccountReinstatement, which is different from the ACSR form and is specifically for accounts locked due to security concerns. After submitting, Microsoft typically responds within 24 to 48 hours by email. There is no phone number where an agent can unlock the account manually, since the process is fully automated for security reasons.
Best regards,