AT&T AT&T Fraudulent DSL Billing Internet

I signed up for AT&T DSL service via their website on 05/31/11 during the order process I selected self installation and that I already had an existing AT&T compatible DSL modem. My online order clearly states that there would be no equipment fee or installation fee. On 06/02/11 an AT&T installation employee arrived at my home, when he informed me that he was there to setup and test my AT&T DSL service I told him that was really nice of AT&T to send someone out to install service for me even though I had selected self installation. When I asked if there was a fee for him coming out he said no there is no fee. After he was done setting up service he gave me a service summary that clearly states no fees or charges which we both signed. Shortly after that I had made several advance payments on my account so I had a positive credit on the account for upcoming months. In August I received a bill showing a $120 dollar installation fee on my account. I called in to AT&T several times regarding this issue and every time I was promise the issue would be resolved except today 09/30/11 when they told me they would not issue the credit. I was transferred to retention to cancel my service because they would rather lose a customer than credit the incorrect charge. I asked several times for an email, fax number, mailing address where I could send the documents proving I was right. I kept my original order confirmation from AT&Ts website, the installers work order, and all of my bills so I could prove to them that I never asked for installation or approved any additional charges for installation. Not once would anyone provide this to me so I could dispute the charges and remain a customer.
 
Without question the worst customer experience I have ever had!
Dates called in to dispute bill: 8/29, 8/31, 9/9, 9/13, 9/21, 9/30