Don't mean to raid on your parade, but it's a very effective way to get your message accross as a consumer. When you cancel your account you are able to include a reason for doing so. That will stay in the system and be reviewed regardless of whether or not you renew your account.

For about 2 months the Oceanic servers were highly unstable and raiding was almost impossible, 4 days of the week it was. Many, many players including myself cancelled our accounts due to the unplayability and lack of compensation, yet I'd say 95% of us still play today.