Question about Outlook Express

I am using the Galaxy S3, sticking with my native app email. My version of Android is 4.1.2.

My IMAP settings are as follows, which are EXACTLY as recommended by Microsoft:

• Incoming (IMAP) Server

  • Server address: imap-mail.outlook.com

  • Port: 993

  • Encrypted Connection: SSL

• Outgoing (SMTP) Server

  • Server address: smtp-mail.outlook.com

  • Port: 25 (I also tried 587)

  • Authentication: Yes

  • Encrypted Connection: TLS

Everything is setting up just fine, and I can receive emails. HOWEVER, there is a problem with the sync. When I delete an Outlook.com email off using the phone, it does not delete from the server, as I can still see it when I log in to my inbox on a web browser. After a few minutes, it REAPPEARS in my phone inbox as though I were getting a new message!

It is quite baffling - can someone assist? Is it a problem with my Samsung email app? With Microsoft?

PS - If you recommend EAS, here is why I do not wish to use it.  I am not able to change the sender of my emails to be my name. It might be a problem with the app or something, as instead it just uses the first part of my email address before the "@outlook.com". For example, it uses "abc123" if the email address were *** Email address is removed for privacy ***.