Hi, I pick up my email using Microsoft Outlook 2010 on a Windows 7 PC and using Apple's email app on an iPad and an iPhone. As of yesterday (when I replaced the monitor on the desktop) I have no email prior to 16:44 on 9/6/2020 (apart from one dated 21/4/2020) in my Inbox (there should be hundreds). If I check via the Virgin media website the same situation.
I've read some threads on here and I appreciate that it's my responsibility to back up emails. However, I doubt user error as they would still be in the .pst Outlook file.
Over the years we have had a steady trickle of cases which have very similar symptoms to yours – namely emails which have mysteriously disappeared. The vast majority of these cases involve the use of Apple devices (iphones/ipads) and/or email clients (such as Outlook) all connected to VM Webmail and therefore each other via IMAP such that a single delete command on any one of these devices is replicated across all these synchronised devices.
Apple is adamant that all such incidents are attributable to “user error” of one sort or another and not to bugs in the apps. Various popular descriptions include - Fat finger syndrome, Bi-focal hit and miss, Doing email on the commuter train, etc.
Below you will find a couple of replies I gave earlier this year on the subject. Nothing significant has materialised on this front since then.