Just as if someone had connected to your mailbox using an email app set up for POP3 that was set to download and then delete Inbox mail messages from the last 6 months.
If that was you connecting a new device to view mail messages then the good news is your mail will be downloaded to the Inbox of email app on the new phone / tablet / computer.
To link this topic to your TalkTalk Mail service, in preparation for direct help from TalkTalk support, please check your Community Profile includes in Personal Information (Click here):
Your name, current TalkTalk landline 'phone and alternate number (mobile preferred). Add your full address with postcode (location). Then scroll down to Private notes to add email address(es), notes and references etc and then save changes.
Check the Trash folder for mail messages that may have been inadvertently deleted.
Compose and send the same mailbox a mail message. Check that the message sends without error, is copied into the Sent objects folder and arrives and stays in the Inbox. Mail not reaching the Inbox could mean there's a Filter rule, including Auto forwarding which is a special filter rule, that's diverting, discarding or blocking mail.
Mail disappearing from the Inbox could mean the email app is downloading and deleting mail messages from the Inbox.
Let us know of any error message, or if mail does not arrive in the Inbox or disappears from the Inbox.
If using email software or mobile email apps, check for software updates and if the email account is set for IMAP or POP3. Collecting mail messages with a POP3 mail account may be deleting those messages from the online Inbox.
Email Settings are listed for TalkTalk managed email addresses.
Hi Megan Jenion, Gondola's advice is great. Please let us know if you find any suspicious filters and forward in place and if you do make sure you get the password on the mailbox changed soon.