I might recommend that if you make the call you might wait until this Viacom situation is resolved. I made the call yesterday and it just seemed to complicate things. I got it done, but it took longer than I would have liked.
Background: Long time customer. We pay the bill on time. I call and complain every year and get free ticket. I actually called in April to complain about a mistake/runaround I had with DTV and they gave me $200 in credits then, so I figured they might be reluctant to give up the ST since I just got free goodies.
(I call, get voice prompt. Instead of going to the usual menu options, the computer voice says something like "if you're calling to complain about Viacom, please say "Yes", to which I reply "cancel service".)
Operator: How can I help you?
Me: I'm ready to cancel. Cable is much cheaper. I subscribed originally only for ST, now you've price me out. This Viacom deal is the last straw.
Operator: But sir, don't you know that we have other channels *like* Comedy Central and Nick?
Me: That's ridiculous. I want what I paid for. Regardless, I know you can't magically snap your finger and make those channels reappear. You can give me free Sunday Ticket to ease my pain.
Operator: Oh sir *I* can't do that, you'll have to talk to customer retention.
Me: What? I thought you were customer retention. Please transfer me.
(On hold for ten minutes)
Operator 2: Hello sir. How can I help you?
Me: (Repeats above)
Operator 2: But sir, did you know these channel disputes don't usually last long? You should write Viacom a letter. Also, I can point you to at a website with the latest news on the dispute.
Me: I don't care about any of that, I just want you to comp Sunday Ticket.
Operator 2: Oh, sir I can't do that. You want to talk to customer retention.
Me: What? I was told I was being trasferred to customer retention.
Operator 2: I'll transfer you now.
(On hold for almost 20 minutes.)
Operator 3: Hello sir. How can I help you?
Me: Before I say anything, I need to confirm you're the customer retention rep.
Operator 3: Yes, I am.
Me: Well, I'm unhappy with my service. I'd like free Sunday ticket.
Operator: Give me one second. OK, sure. You've got it, anything else?
So the point of the above, was that at least for me, this far and away the easiest negotiation I've had with them, but it took quite awhile to get connected to the correct person. I am guessing if you wait until the Viacom situation is resolved, your call may go a lot quicker.