Is "delinquent credit card debt" the total outstanding balance or is it just the amount overdue?

I could be either one. If you haven't made a payment in 3 months, they likely have closed the account and are preparing to take action to colllect the whole sum from you, not just the minimum over the past three months. You're best bet is to call them and find out what needs to be done to put the account back in good standing.