Yep... Call them up. Wait for like 30 minutes if you call in the middle of the day. Tell the first real person you speak to that you're thinking about cancelling your services and want to speak to someone in the Retention dept.
Make up some bullshit about how you've talked with the dish companies, etc. and that they can give you the same services you get now with TWC for like $30 or more less a month. Ask them what they can do to keep you.
For the most part, this has worked 99% of the time for me. The one time or so it didn't, I call back a day later and get a different person on the line.
Just like my HBO example, they'll even take half off on some things.
i just told them to give me the introductory offers or I was leaving. I told them I could either leaven and go to fios or easily re-up in my wife's name and get them anyway, so why don't we just save everybody a lot of time and just reduce my rate.