hotmail locked

My mum has been using a hotmail.com email for a couple of years, she doesn't overly use it but recited some needed and a lot of junk mail to it. In the last week she had been trying to access it and it won't let her saying that someone else might be trying to use her account. She has tried filling in the form several times but doesn't have enough info. She even got it to ring her home withan access code and out still displayed same message. She needs to access the account as she had been receiving emails from her lawyer to this account and on a more personal level there are emails from her brother a couple of years ago about their mothers funeral including the proofs for design of sheets. Please help she is devastated at the possibility of losing this. Her email that she can't access is *** Email address is removed for privacy ***.