Can I get access to a Prerecorded phone conversation that I had signing up with DirecTV?

I am having a contract dispute with DirecTV. When I was signing up for service over the phone, their sales rep assured me multiple times that my movie channel package would remain free as long as I stayed a current customer, instead of the normal 3 month free period they offer all other consumers. However, after my 3 month period was up, I started getting billed for the movie channel package. I've spoken to several customer service reps and managers about the situation. They said it should have only been the normal 3 months, but I told them that's not what I signed up for, and to listed to the phone conversation. They said they listened to it, and still said that' what they told me about the 3 months. However, they are lying. So now I want to get a copy of this phone conversation they have so I can present it to a lawyer for compensation.