AT&T long distance 800 # magically becomes 900 #

I got my phone bill from Qwest for July and noticed a charge from AT&T long distance added to it. Two calls totaling 12 minutes for over $100. I called to find out what was going on since I have a long distance block and 900 block on my phone. The woman I talked to said it was on the internet and it was a porn site. At the time of the porn call I was at work and my sons don't have access to my computer at home. She promised to have my account credited for the full amount within the next 3 billings. Four billings later it was still there so I called again. A man said the woman had screwed up and the call was made from my phone so I need to pay it. He would not give me his name, his supervisors name, a reference number or a phone number. Wonder what they were hiding. I called Qwest back and they said that there are some 800 numbers that people call that forward to 900 numbers without you knowing and AT&T is the company providing them. The number I supposedly called is a porn number on an island on the other side of the world that I have never heard of. If the number was accessed without dialing 800 first it would have been blocked or station-to-station. Unfortunately I am still fighting with AT&T. If anyone else has been fighting a similar battle I'd be interested in know about it. Can you say class action?