First, you need to answer the lawsuit. Making a phone call or sending a letter does nothing.
Your answer needs to have a legal basis - saying, "it's my debt but I just can't pay," doesn't help you and isn't legally proper. That's an excuse, not a defense.
If Chase didn't sue you but a debt collector did, make sure the debt collector attached proof that they own the debt. If they don't prove it then you have a defense.
If the credit card agreement isn't attached, that's a good defense also.
In other words, make them prove the case. Make them show the agreement, proof of ownership, and how the balance was calculated.
You may owe Chase money, but how MUCH money is a valid question that must be answered. Also, proof that you owe THIS particular entity money is a good question.
Take nothing for granted. If they make a claim, make 'em work for it.
Once you've done that, you're going to want to call the lawyers and tell them you've got nothing they can take. Make them an offer to see if they settle it.
If not, show up in court and let the judge decide.
Good luck!

