Not a happy customer

I have only been a customer of AT&T since February 27th. Billing has been a nightmare and I spent an hour yesterday on hold and speaking with a customer service representative, who told me that she would send an email and a supervisor would contact me within 24 hours. I waited and no call came. Called again tonight and waited on hold 20 minutes before I was passed between 3 different individuals, then was forwarded to a recording that said the office I was trying to reach was closed (at 8 pm, hours are until 10 pm). I was hung up on. I am completely frustrated. Anyone else had any luck resolving billing issues and how did you get someone to help you? I have been getting the same song and dance from every representative, "I can review your bill with you" but they cannot explain to me why I am being charged so much for a little over a month of service. I have an "adjustment" on my bill of $300 with no explanation. I am now being charged $145 a month for Direct TV when I used to pay $105. They cannot explain these things to me.