Silly blonde needs some help =)

I have an interesting situation that I would greatly appreciate some input from the experts out there.

This all started back in the beginning of 1999. At that time, I had a boyfriend/business partner in a new venture. He had agreed to co-sign a $10K personal loan that I took out with Wells Fargo Bank

Anyway, about 4 or 5 months later, our business relationship (and our personal, damn cheater!) soured and broke down altogether. He offered to buy me out of the venture for $5K which at the time, I rejected. That offer was then rescinded and I did not receive anything further from him.

I then made the decision that screw him, he screwed me, I would NOT pay the loan off and leave it to him as compensation for my share in the Venture. At that time, the balance was down to around $6K or so.

He did send me a few warning emails to pay the $6K to wells fargo, or else... but from that point forward, I never heard a thing from him again.

So today, I receive in the mail a letter from a Collection Agency saying they are collecting a debt. The letter stated that I owed a total of $16017, which including an Amount figure of $11500 and Interest of $4500. Interestingly, it states at the top that the debt is from my ex business partners company, ie Re: ABC CORPORATION. There is nothing else of substance at all in the letter.

So what I find interesting is that where they pulled that figure of $16K from and how I can owe a company this amount that I never had any dealings with. Yes, my ex-partner co-signed the loan but we never had any contract or anything signed etc, except the loan papers from Wells. How is the debt even in his company name?

So I am looking for advice as to what to do now. It says that I have 30 days to dispute the validity of the debt.

How should I go about making this go away?

Thanks so much all and I know, never mix business and pleasure...I learned that the hard way...