Are you looking in the online mailbox or just the folders in an email client or app?
If your mail is on the TalkTalk Mail platform i.e. talktalk.net, lineone.net, tiscali.co.uk or others in the tiscali family then:
Check Spam and Trash folders for mail messages that may have been diverted from the Inbox and Trash for mail messages deleted from the Inbox.
If it was part of a conversation then check in the Sent objects folder for messages in that conversation.
Does the sender still have a copy in their Sent folder?
Hi LINDAWORRALL, you won't go wrong following Gondola's advice. Please let us know how you get on.