Missing emails on UK Yahoo


New Email
I've been using Windows Live Mail for many years on a Sony Vaio with no problems. Because of problems with my Vaio (not Yahoo related) about 1 month ago I started to view my emails on a Samsung tablet but still used my Vaio to send emails and a week ago I got a new Microsoft Surface Pro to replace my Vaio.

When I set up the new MS Surface Pro to use the MS Mail App it only downloaded emails for the previous 2 weeks. I logged in to Yahoo mail online and there were no emails in my inbox dated before 15 September. I sent an email to the Yahoo Mail Restore Team and a number of emails have reappeared for the previous 3 weeks.

I have a number of questions;
- do Yahoo remove emails from my inbox, if so is this normal or because I used my Samsung tablet or new MS Surface Pro?
- is there a setting on the MS Mail App that deletes emails from Yahoo after a number of days? If so, can I change the setting?

Hope someone can help

Thank you