Here is an article (Troubleshooting no internet connection) that you may find helpful, this will guide about basic troubleshooting you may also check if there is an ongoing outage affecting the service, available here. How to Check for NBN Network Outage
In this particular issue affecting the service, we took the liberty to ran an initial test to the connection. The result shows that the service has been connected for 3weeks 2d 10h 58m. You may refresh the modem/router's connection by turning it on and off for 3-5mins.
In the event that device(s) connected via Wi-Fi is having issue we did an article about basic Wireless Troubleshooting available below.