Are you able to send us a screenshot of the "westnet" logo on your phone? Moreover, can you send us a PM with your TPG mobile for us to look into your account? Thanks!
Here is how to send a PM - https://community.tpg.com.au/t5/Welcome/How-do-I-private-message-PM-in-the-community/m-p/4093
What troubleshooting have you tried so far? Have you tried to use another smart or mobile phone to replicate the issue?
Was it working fine before? Have you tried to manually select a network?
If you are still getting the error or a different network, shoot me a PM with your Customer ID or mobile number to assist you.