Yeah I dunno it's a bit of a strange conclusion here. I guess I understand if the O.P is maybe under pressure from others or was time limited in pursuing this project. It's hard to tell from the last post if rolling back the firmware got the modem to sync or not.
If they were going to keep on, the thing that needs to be figured out is if sync is occurring, or what phase it's getting to and as you say whether he has the wan setup configured properly.
It seems possible the O.P didn't roll firmware with ppp(oe) support because if you look at his lsmod command, there's no pppoatm listed. I dunno, it's a weird game haha.
At least with how things work here, sometimes the wholesale provider can cut access for 24-48 hours or something if it detects incorrectly configured devices.
Sometimes the internet provider will block access if the mac address of the dsl interface changes (almost certainly going to happen when you switch to using openwrt) for up to 1hour, at least that's how it works here.