It clearly shows that there's nothing wrong with your TPG Internet and the issue appears to be on the Wi-Fi.
If you normally connect all your devices via Wi-Fi, these community articles can help you in improving the wireless connectivity performance.
Easy Steps to Improve Wi-Fi Connection In Your Home
Wireless Channel on your modem - what is it and why should I change it?
Wi-Fi troubleshooting steps - No Internet/Connection
Please make sure that when running a speed test, there should be only one device connected and there are no programs running on the device background to get an accurate result.
We'd like to perform further troubleshooting and arrange a specialist to contact you for assistance, @shyam1231.
Please PM us your best contact number and most convenient time to receive a call. We'll wait for your PM. Thank you.