Please do a quick check that your Community Profile includes in Personal Information (Click here) your name, current TalkTalk landline 'phone number and an alternate number (mobile recommended) and address with postcode (location). Then scroll down to Private notes to add email address(es) with any relevant other notes and finally save changes. TalkTalk's Community Team OCE will then locate your registered TalkTalk details.
Is your mailbox on the TalkTalk Mail platform? i.e. you sign in to TalkTalk Mail here and see your mailbox and Inbox messages? Have you checked in the Trash folder?
Please also check that there's no Auto forward or Filter Rules active that might be impacting the receipt. Main Settings Menu (top right triple line icon or cog icon on mobile versions) > Settings > Mail (select right arrow by Mail or Email in the left panel) > Select Auto forward and Filter rules in turn to disable any that happen to be there.
Do you have, from the senders of the mail messages, the error message / codes bounced back to them?