Welcome to TPG Community!
Your free TPG email is on a POP3 account.
The emails that you received will be automatically deleted on our server after 45 days in which your devices (Computer and iPad, etc.) will need download the emails that you've received separately to keep them.
The emails that you deleted on your computer will not reflect or sync with other devices since they saved a copy on their own.
What is POP3 email account? Check this link for more information.