Who has to supply the proof?

[4llll]

An attorney contacted me about 4yrs ago about a credit card debt from 4 years prior. This was the very first time I was notified about this debt. He told me that he purchased my delinquent debt from Chase Manhattan Bank. I told him that I never had acct. with this bank, the only one credit card that I had at that time was with Providian and I had paid the total balance off at one time and closed my account. I remember that I could afford it because I had just sold my townhouse and paid all of my debt off with the proceeds. He told me that the only way I could settle this law suit is to provide him with a copy of the check that paid that account off. The last time in court with this attorney, the judge had just realized that he never provided me with an account number and he wasn't sure if the debt was from Chase. I told the judge that at the time of the debt I had my checking account with Bank of Boston-which changed to Fleet, to Sovereign, to Bank America. I told her it was very difficult to get some one to research my account and supply me with a copy of the cashed check from over 7yrs ago. I also told her, when I had my acct. with Providian, they were also going thru a merger or selling their credit card business so it was also very hard to gave someone research the debt on their side.
This attorney has been harrassing me for over three years and depositioning me, he knows I do not have an attorney and he keeps threatening me with more fees. I don't know how to settle this issue, I have been trying to research 8 years worth credit issues with no avail. I just need to know what my rights are and if anyone could help me find an easier way to settle this issue of a debt. I paid off many years ago.

Please help!