Hi there,
As someone who has an addictive personality and also plays Wow, I get this. Here is what I do - I do one month on, one off. So i get a card for one month, and then not buy one for the next month. Its painful at first, but eventually it got me to playing a more reasonable level. I wonder if you could contact them to see if they could limit your playing time to certain times of the day or week - like only weekends or only 2 hours in the evening.

Also, When you play, remember that it is bad for your eyes and brain if your playing for long hours. Every hour take a 15 min break. Go outside, breathe some fresh air, pee,(or poop :P) get a drink, call a freind.. try to get involved in something else, and if you get involved, see how long you can continue it. For instance call a friend and get in a long conversation. Try starting with 15 min and then working up to longer periods of time.

Its also good to develop other hobbies - what do you like to do thats interesting for you? have those things accessible at all times, so you can choose other activites. Do something goal oriented - like painting or writing or drawing or even cooking and baking!

if it has become a serious issue for you - contact them and have them block your account altogether. I have heard of them doing this for people before. Contact a therapist or an addiction center - dont be ashamed because its not a drug - they have heard of this addiction before, trust me.

Take it one day at a time. You can do this!