Supersonic router settings

[schuits]

So unfortunately my FIL has supersonic. The internet stopped working and I couldn't access the admin page.
I factory reset the router (zyxel VMG3625-T20A). What settings do I need to setup? Is there an account username&pwd that I need or something.

I tried contact supersonic but that didn't work.
TIA

 

[Drifter]

Yes, you would need to enter username and password as provided by your ISP.