If your speed seems to be running slower then you would expect,
first suggestion would be to check and see if there is an outage in your area, you can check that here;
https://servicestatus.telstra.com
Secondly, depending on the NBN type there are some troubleshooting tips to try, for example with FTTP try doing a reset on the NTD, and for all do a reset on the gateway devices.
Thirdly if the issue is ongoing then it might be worth speaking to the NBN Assurance team on 1800 TFIBRE (1800 834 273)
first suggestion would be to check and see if there is an outage in your area, you can check that here;
https://servicestatus.telstra.com
Secondly, depending on the NBN type there are some troubleshooting tips to try, for example with FTTP try doing a reset on the NTD, and for all do a reset on the gateway devices.
Thirdly if the issue is ongoing then it might be worth speaking to the NBN Assurance team on 1800 TFIBRE (1800 834 273)