Hi Laurie767
The normal reason that mail messages disappear after a set time is that someone has set up a mail collection using a POP3 account to connect to the mailbox and is using a setting to leave messages on the server but delete those messages after a set number of days. The typical defaults are to delete after 14 days or 30 days. 5 weeks would be unusual but I'd guess delete after 30 days might be what we're looking at here.
The question is, has the account owner set up or changed a mail collection, using say Outlook or similar, and got the collecting account as a POP3 account with advanced settings set to leave messages on the server but to delete after 30 days? Or set up an archive of mail after 30 days?
If not the account owner then consider that the email password may have been compromised and should be changed to lock out any rogue or unauthorised mail collection. Scan her email devices for any potential virus or malware that might be capturing passwords.
The Reset your password now button in the help article Changing your email password will take her to password reset and recovery.
If she has set up password recovery options, in advance, that are recognised from the *****hints, then she can send the alternate email address a link or the mobile a 6-digit code to authorise a password reset.
Let us know what the situation is regarding mail collection from her lineone account and if you / she needs more help with changing the password to secure the account so it can be tested just as a webmail account to prove that's working ok.
