If you really really want out of your subscription, call for a replacement card. The next time WWE goes to bill you it'll cancel out your order due to a new card number. I had to get a new card due to mine being jacked up and forgot to change my WWE Network subscription. When they emailed me I was like "oh yea...don't care" I have so much other wrestling that I want to watch, with a DVD collection that is growing seemingly daily, I barely watched The Network anyway. Only thing I watched on there was the PPVs and Legends House and Legends House is over.
I have a huge backlog of Continental, Puerto Rico, Portland, SMW etc that until they start putting up more territory footage I'm not going to go back.
EDIT: All that said they are finally doing a free trial the smart way, without a credit card. Not sure how I feel about them trying to hype Monday Night Wars for immediately after Raw. It's pretty late for such an important show.