Someone probably brute-forced her password and used her account to send out spam/phishing/fraud emails..... Microsoft probably got an influx of complaints, and as it the usual case chopped off her account with no further warning as per the TOS.
Chances of her being able to do anything about it ? None.
You get what you pay for in this life. Perhaps it's time to look at hosting your email somewhere you pay someone for it, at least then you get a phone number you can shout and scream down.