I've just seen your post on another thread saying you've discovered an unauthorised Auto-forward and that you've deleted that.
If someone has acquired access to your mailbox to set up that auto-forward then you must change your password to secure the mailbox.
Access the email address via the TalkTalk Mail sign in here
When you sign in via TalkTalk Mail you have the ability to set up Reset details for a self-help password change. Update your reset details is an option on the main menu.
Please then use the Reset your Password option.