For customers who want to pay their bill, we have created these community articles, which may help in accessing the TPG My Account to process payment online.
If you're not aware of your account customer ID , username password, you can check the welcome email we have sent when you sign up with the service.
This article may help you as well if there's a need for you to reset the password:
In your case, we can see that the payment has been processed.
Should you need further assistance, feel free to search community for help or chat with us at https://www.tpg.com.au/support/contact/ and we'd be glad to assist you.