I know how it feels. But you can't just NOT pay CitiBank, or any other legitimate bill, without serious consequences. Especially now when we are in the worst financial crisis our country has been through in almost 80 years.
If I were in your shoes, I would try to find a debt relief agency that will help me make payments to Citibank, and other creditors so I don't have further credit problems. It's tough, but you can't cut your nose off to spite your face, when dealing with credit issues.
Be a man, take a deep breath, and take care of things!