AT&T customer service escalation

How can I escalate issues with AT&T customer service?

I called customer service to apply corporate discount to my existing account and I got transferred to 4 different people. 

The first agent had no idea about corporate discounts and I believe she did not understand the word corporate itself. She kep asking me to add auto reload to my account to get discount. The second agent did the same thing whereas the third agent pretended to understand my question and tranferred me to 4th agent. The 4th agent conveniently kept on saying that my line is bad and she is not able to hear me at all even when I was shouting at the top of my voice.

I am frustrated with the call that I had with AT&T and need to vent the anger on a supervisor. Wasted last 45 minutes getting transferred from one agent to another without any solution.

The chat does not work on the site either, It keeps on asking me to logon after opening in a new tab.

In short, I want coroporate discount on my account but AT&T has failproof safety net to not provide that to me. I dont know how AT&T can hire such agents and expect customers to be happy with their service. The only reason to stick to it is extended coverage in the west coast.