I've cancelled Rogers up here in Canada in a painless, lie free, asshole way without resorting to swearing.
It's easy, just say you want to cancel, act like an imbecile, refuse to be transferred to their retentions department. When they offer you a better deal, or ask why, just repeat "I want to cancel" over and over, and if they still give you guff, ask to speak to their supervisor (all after getting their name and agent number).
I was able to cancel everything in under 5 minutes.
Remember, you don't have to be nice or polite to them when they're trying to upsell.