Welcome to TPG Community!
We have located the account using your community details.
As per checking, your account has exceeded the monthly allocated data for peak hours, thus your speed has been throttled.
If you check your previous data usage report with ADSL service and compare it with NBN, you will see a big difference and will better understand why this issue is happening.
To avoid this from happening again, we recommend that you consider upgrading to a plan with unlimited data.
We can have an account specialist contact you to further discuss the matter. Feel free to PM us your best contact number and most convenient time to receive a call.