How should I proceed?

In 1994 I was issued a Capital One credit card, with a 1,000 limit. I had a 900.00 balance on it, and was ahead of my payments. A travel company charged over a hundred dollars to my card without my permission, and I was refunded. However that had thrown me over my limit, and until I got it taken care of, I had acquired over the limit fees, and late fees. I tried to catch up, but soon after lost my job, and was unable to pay on it for some time. The card of course was canceled by Capital one. Around 1998, I was sent a letter from a CA, saying I owed approx. 3,000. When I inquired how it was so much I was told interest charges. I wrote them a letter stating that I wanted a detailed statement showing me how much I charged on the card, and how much I paid. I never heard from them again. Fast forward to 2000. I was contacted by a second CA, and made payment arrangements with them. In Jan of 2001, the CA called me to inform me that my payment plan was no longer acceptable. He gave me three options. Pay half of the whole debt, make payments of 400.00 montly, or put down 1,000, and continue my previous montly payments. When i refused saying I could not met those terms, he became nasty and accused me of not taking responsibility for my debt. I hung up on him, and havent heard anything more from them. It wasn't until a few months ago did I get a letter from portfolio recovery associates, stating that I now owe over 6,000. My question is, can they still come after me after 14 yrs on a credit card? Am I still obligated to pay? Isn't there a statute of limitations? What do I say the next time they call? Oh and i've checked my credit report and there is no mention of capital one on any of the three reports.