Managing personal Outlook.com account settings, security, and privacy
Maybe these personal notes can be of some help.
Open a locked account
Can be caused by unsuccessful password reset, failed login verification or questionable activity on account. Please note that it is possible to use EMAIL even though the account is quarantined.
https://support.microsoft.com/en-au/help/13956/microsoft-account-locked
“To unlock your account, you must enter a security code you receive via text message from Microsoft. The phone number you use to receive this text message doesn't need to be associated with your account. It doesn't even need to be your own phone number. If your phone doesn't receive text messages, ask a friend or family member if you can use theirs. Microsoft won't save this phone number.”
“If you see a "usage limit exceeded" error message when requesting a security code, this could mean the phone number has been used too many times in a short period of time, or that we've detected something suspicious about the phone number.Then use a different number.”
Please let me know the result of your action or if you need some more ideas.
Best regards
Janne
(an ordinary Swedish MS user)