Just to clarify, most civil summonses don't require an appearance, they require a written answer to be served on the plaintiff by mail and filed with the court. There is a fee for filing, usually around $250-350 (in Minnesota, anyway; I'm guessing as to any other state), depending on whether or not you want a jury trial. You can also file a petition to proceed
in forma pauperis, but do this well in advance, as it may take a few days to get your petition granted, and the deadlines for answering do not get extended just because you file an IFP petition.
Attached are the first two pages of a three-page Answer I recently filed for a client.
This is an example only. The text of an answer and the defenses you would use vary widely depending on the complaint, the jurisdiction, the type of debt, and more. Don't go copying this, because it probably won't apply to your case.
I just post this to give you an example of the type of response required when you are served with a complaint. I would still recommend you consult with a lawyer, or at least do a lot of research into your state's procedural requirements.
Edit: FYI, Citibank is not a debt collector, so the fdcpa defenses probably don't apply.[/i]