Northland Group credit card debt past statue of limitations Northland Group Nationwide

I'm currently a medical student who studies abroad. I had many medical illnesses myself during my undergraduate years (2001-2005). I cant even recall having an unpaid debt with citibank, yet today I received a call from Northland group requesting I send them money on an account that had fees and interest total up to $1300! Since I have been in grad school, I have vigilantly kept an eye on my credit reports ( due to the fact that I am on private student loans). I called citibank and the woman I spoke with was not able to help me. She transferred me to their collection agency (not the same as the one I spoke with). I told the man that I never received any notices nor phone calls regarding this debt from citibank. He informed me that they did not need to??! I would assume if I have a valid debt from a credit card company, they would at least send me a bill so I would know to send a payment in. My credit report has stated that I have a $0 balance on my visa citibank card and the last activity was in 2002. The balance the rep with Northland quoted me was $1300 with interest and fees, although the credit limit I see on my credit report was only at $600. He told me he could settle the account for $400.
I have already been duped by a collection agency into paying an old account I did not owe money for (Cingular wireless made billing errors on my last bill in 2003). I paid the bill finally in 2008, and the collection agency was able to put up a negative account on my credit report once I paid it (nothing was on my report prior to paying). Please help!! I'm not sure what to do right now! I've worked so hard to bring up my credit score to obtain loans for school, I do not want to have to go through this ordeal again. Thank you so much for your help!

Medgirl83
Lake City, Florida
U.S.A.