Here's the secret to cancelling an AOL account, from a previous AOL call center rep:
When you call to cancel, you will be directed to someone whose job is to save you. Tell them "I want to cancel" and then when they try to save you, just say "Oh really, that means nothing, I want to cancel." It will take a few minutes before they give up and cancel the service.
Part 2, and this is the most important part. Call back to speak to billing to verify that saves actually cancelled the account. The billing department HATES the saves department because they get to deal with customers after saves screwed them, so they WILL be honest about whether or not your account is scheduled for disconnection.
And, btw, new policy is that they can, actually, make you account disconnect on the next billing date. Its a good thing. You don't get money prorated back to you for unused time, so you might as well have it for the rest of the month.
Oh, and I've heard this before. That rep is an ass.