If you were on the phone with tech support or the installer for three hours, it's hard for us to add anything meaningful without a lot more info, really...however:

Did they say the internet light on the modem should be green other than red? (All modems are different, I used to have to ask all these questions, sometimes like pulling teeth, when I did cable internet support)

If the internet light is red and it should be green, I'll hazard a guess that the modem was not receiving its provisioning correctly (although that might be what the dsl light depicts) my best guess would be that the modem is not receiving an IP address, which means they may have a DHCP server issue on their end, or they have literally run out of ip addresses to give out (quite possible if it's older infrastructure or your area has grown faster than at&ts infrastructure has)

I just looked up what your lights mean - is there any sort of switch or setting for "bridge mode" on the modem, maybe on the back? Other question is, do you have a computer directly connected, or is there a router to allow a laptop or other computer to connect as well?

I assume the tech just enabled it outside and you've been working on this yourself, and with tech support on the phone?

Normally I would ask if you had connected between the modem and the computer with an ethernet cable (probably came with the modem, looks a bit like a phone cable but larger, and the wire part is round not flat) or a regular telephone cord - yes, it's possible to fit a regular phone cord into that jack - if you used the cords supplied you should be ok.

Assuming that, you have the dsl filter/splitter connected to the phone jack, then a regular phone cord between that and the phone line in jack on the dsl modem, then an ethernet cord between the computer and the modem? Sounds like that is good since you're getting the ethernet light on the modem.

Looking into it further it appears bridge mode would be an internal setting on the modem, so I think it'll be down to at&t to sort out on our end, sounds like modem is not getting an IP address. Once that's sorted from the basic setup you've described, you should be ok.

One thing to consider once that's sorted, if the computer has been online before with dialup, you may need to disable that but hopefully the setup disk will have taken care of it.

Good luck with it, hope they sort it out promptly for you.

On the third day we asked for a status on the case number and AT&T said it had been "resolved" with no explanation recorded.

I guess we will never know.

So presumably you have service now? I don't know about the official policy about contacting you or not, I agree I'd prefer to be contacted rather than just trying on the off-chance but I guess the main thing is resolving it.

It sounds like it was on their end, perhaps one of the scenarios I suggested.