The only thing you say at this point is "I request you to close my account effective immediately. Is my account closed yet?". Anything else you say (e.g. "You're the reason I'm leaving" or even "I'm moving to Mars") will be used as conversational leverage against you.
Other than that, have fun with it. I got a manipulative rep when I canceled Sirius and told her I already threw away the radio when she tried to extend the contract. She was not prepared for that. :)
Other than that, have fun with it. I got a manipulative rep when I canceled Sirius and told her I already threw away the radio when she tried to extend the contract. She was not prepared for that. :)