How can I cancel my iphone6 plus pre-order? It shows that I cannot cancel the order online.

I placed an iphone6 plus pre-order online, at 12:15am on Sept. 12. Ridiculously the order confirmation told me that the iphone 6 plus will be shipped at the end of November. I cannot understand why they are doing it. But I do not how to cancel my order. Will it work if I call and talk to an agent? I have tried to call twice, waited for an hour and the called got cut off. What shall I do in order to cancel the order. At&t is just wasting my time and money.