I doubt the ATA had anything to do with it. If VOIP has failed, doesn't mean your high speed internet connection has failed and it's possible to have connectivity. Verizon's Tier 1 is a huge waste of time. You're never going to get anywhere with those clowns. My guess is your modem dropped the logon and pswd for whatever reason. Verizon's Tier 1 fix for everything is scripted hard rebooting sequence, but I digress.

I'm also a Verizon DSL customer and my service problems with them were an epic.

I assume your modem is also a router, b/c I didn't quite follow when you said your ATA is in front of the modem?