Any allegation to which you don't directly respond will be treated by the plaintiff and the judge as though you agreed to it.
You have three options to respond to each allegation: you may either admit it, deny it, or say you lack knowledge or information about it. Saying you lack knowledge has the effect of a denial, forcing the credit card company to prove the information. Most answer forms have a box you can check to generally deny all the allegations in the complaint, if you don't want to go through them separately and if you don't admit any of them. Keep in mind that the company suing you has the burden of proof on all the allegations it makes in its complaint. If you admit an allegation, you're making their job easier because you're saying they don't have to prove that allegation. They're the ones taking you to court – make them prove their case. You must answer truthfully, but denying an allegation doesn't mean that you're saying it's false or that you're trying to avoid your debts– it means you're saying the plaintiff must prove it. For example, if the complaint states that you entered into a credit card agreement with the plaintiff, but the plaintiff is a collection agency who bought your debt from the original credit card company, you should deny that allegation. You never entered into any agreement with the collection agency itself. It's possible your credit card agreement has a clause allowing the credit card company to sell the debt to a collection agency if you don't make a certain number of payments on time, but that's the collection agency's responsibility to prove – not yours. Specifically make them prove the amount you owe. Your debt may have changed hands multiple times before it was taken over by the collection agency that sued you, and somewhere along the line there may have been an error in calculation.