seize bank accopunt

No, a CA cannot seize your bank account at least without a judgement first. Even then, social security income is exempt.

The key word is "tried" to serve you papers...or did they get a judgement against you without serving you properly?

Since credit card debt falls under open ended accounts, the SOL for such debts is 4 years in Illinois. So you should first check whether the SOL has expired or not before you start paying. This is because, a creditor cannot legally collect the debt after SOL expiry, but if you make even a small payment towards the debt, the SOL will restart and the creditor can again sue and recover the entire debt.
The creditor can never seize your bank account without a judgment. Moreover, even if they bring judgment against you, they cannot garnish your ss benefit.

SOL for Illinois is 5 years, not 4.

http://www.debtconsolidationcare.com/statute-of-limitation.html