What I read was that client side had a 150Mb limit that was increased to 500.
Century Link gives me 1 Gb.
What is Century Link?
And, if she was sending email on her personal computer from home (or a phone) with or without an alias, they should be backed up on her service provider’s (Hot Mail, gmail, etc.)servers - no?
Tinfoil hat or Clancy time- - maybe she was using an Internet Café and their computer and servers crashed ;-)