Put the sage in regular mode for them via reset so they can interact with it and signal check. i dont think they can read it in bridge mode.I did call them two weeks ago, they did a signal check and all was fine however when I put it back into bridge mode the guy on the phone said he could not access the modem etc
As far as I know I don't need any ppoe creds, never needed all these years and it was working flawlessly.
Edit: all they are saying on the phone are basic things, factory reset your modem or router, power cycle bla bla.
The easy way is to go is to shitcan your asus and use the sage,