[VoiceOps] Help Navigating AT&T call trees that go nowhere

I have an issue with a local AT&T tandem rejecting calls for AT&T some subscribers (entire NXX from what we can see). We've tried to call pretty much every number we have and gotten nowhere. Either the person can't help and transfers us to a place that can't help, or they give us a new 800 number to call. In one instance the new 800 number was a medical facility, not AT&T. Does anyone have a way to actually reach someone? One of the numbers we got is from an actual AT&T technician, and even he couldn't get through to someone to look at the issue. Thanks Shawn