FIRST STEP, I would encourage you to check into the Federal Communications Commission (FCC), which is the governmental agency that handles complaints over these companies and the problem that you are having. Here is the website to find out about the necessary steps to file a complaint (don't file the complaint just yet - it will be much easier to gain the knowledge you need and then have one more conversation with the company first to get your problem resolved and it will save you lots of time):
http://www.fcc.gov/cgb/complaints.html
NEXT STEP: Contact AT&T back and be very sweet when asking to speak with a manager, (as it seems as they are the one holding everything up - interesting they hung up when you tried to do a conference call??). If anybody (CSR) says they can help you, thank them ever-so-sweetly and tell them that you really need to speak with a manager (without telling them the specifics of why). Be gracious and thank the Customer Service Rep(s) for their help, but keep your focus to get to a manager, BUT DON'T GIVE UP - ONLY SPEAK WITH A MANAGER!!
When you do get connected with a manager, take really good notes and do the following:
1) VERY IMPORTANT STEP: BE VERY NICE and ask for the manager's name right away (first and last name if you can get it) and BE SURE TO GET THEIR direct contact phone number / extension (this creates a situation of accountability on their part) - I ALWAYS start out half-joking with the person I am speaking with by telling them something like "heaven forbid we would ever get disconnected....... but if were to happen, then I can easily call back and reach you." Laughter is the best medicine for most situations - so this statement usually gets them chuckling (I even laugh with them).
2) advise the manager of what you need done NOW and also tell the manager how many phone calls you have already made where this problem has not yet been fixed. If the manager gives you a run around and does not help you, then go to step #3 below
3) advise the manager that you are prepared to contact the FCC and file an online complaint if your situation is not resolved today. Again, tell the manager what the solution is that you need to have done today. If the manager does not want to help you, then you can tell the manager that you are filling out the Complaint Form #475 as you are speaking with them - this will tell the manager that you mean business and ARE CREDIBLE and that you know what you are talking about. They will also realize that you have their contact name and telephone number to put on that complaint form and hopefully will HELP YOU RIGHT AWAY.
4) as an alternative or one last resort next to call the Attorney General's Office, if the manager does not want to help solve your problem, you could ask to speak with the manager's supervisor and then repeat the above steps.
I hope you get someone that will help you, S.! I've been there and done this in the past. My husband uses the above steps and he's even taught me and THEY WORKED FOR ME!! Good Luck!!