Hi @Mega ,
If you only wish to get a emails from the old TPG E-mail address, you can create an Email Alias to your current TPG Email with the same E-mail address from the inactive account, by doing this you will also receive the emails being sent to that inbox.
You may visit this link on how to manage your Email Alias
Let me know how it will go and should you require further assistance.
Is there any way that I can breifly use an old TPG email to recieve an email? I would need this email so I can remove association with the email from a service I use.