Have you tried different channels like 1, 6 or 11?

The problem has been fixed. Upgrade the latest firmware.

Is there a battery in your NBN box? You must have tried to restart NBN box and C9, right? Ensure the NBN box has no power source including the battery. Power off C9. Power back on the NBN box and C9....

when i try upgrade i get invalid file format... Did you extract the file before upgrade? Check the correct hardware version on the bottom of router itself. There is a troubleshooting guide about how...

No idea... Confirm with India customer support? What's the model number? Do you remember what you've done to troubleshoot?

You cannot open the website, cannot login or cannot receive&send email? Directly connect to your modem and check if it works.