I have had an account with TPG for more than 8 years and it was originally registered with my housemate's name and he left Australia for good few years ago.
I have updated most of the details in the account including address, email and payment details but I am unable to change the name.
How will I be able to do that?
Welcome to TPG Community!
Check out this thread on TPG Community, which should address your query:
Changing account holder
Please refer to the Community Manager Krystle's comment.
Let us know if we can be of further assistance. Cheers!