Email problem

[Bill Atteridge]

BTinternet mail account used through Outlook on home computer. At work of remote, other machines used and mail sent and rec'd via Yahoo.
However, Sent emails from remote machines are not posted in Sent file on home Outlook.

BT IT Helpdesk says system 'stuck' on POP3 and needs to be on another setting.

Any suggestions? Many thanks in advance.

Bil Atteridge