I have a Telstra TG800 Modem and have tried to use the Parental Control - Time of Day Access Control for a specific device and have used the device's MAC address to identify it (got it from Advanced Settings), then set the times and days for blocking the device but the time has come and it did not block the specific device from accessing the internet as my son was still able to play the game on his laptop. Is there something I missed in setting up the control?
Can the device connect by both WiFi and Ethernet. If the it can it has a separate MAC address for each interface and blocking has to be set up for both MAC addresses. Another thing to check is that the modem's date and time is correct.
Which mode did you use "Allow" or "Block"? If you used "Allow" and have different times on different days this can cause the access to be allowed on some days when it should be blocked.