Your course of action would depend on your ultimate goal for this account. Are you just going to ride it out until it falls off or are you going to try and PFD it and have it removed early.
Have you paid on this account since it went delinquent, have you acknowledged the account or agreed to repayment since that time?
Some companies try suing under "breach of contract" for CC, which falls under written SOL and is usually longer.
In MO, one defendant won because the CC company couldn't produce a written contract that was signed by the defendant, so SOL fell back under open contracts.
This is becoming more common. Some states are allowing it.