SOL Question for a debt being collected by Asset Acceptance

HI, I am trying to find the exact date of my last payment to Cititbank. The account has been past due for three years, now, and the SOL is next month. I got a bill from Asset saying they owned the account. I asked for debt validation. All I got was a letter saying the account was my Citt account and the balance was xxxx and the fees are xxxx. They listed an SOL of Sept 2003. That month and year are correct. They sent no other information as proof the account is mine. Now Asset is reporting the SOL on my credit reports as November 2003. So, I think they have broken two laws. The continue to report a debt they did not validate, and they changed the SOL. What should I do? Citiband has no information on charged off accounts.

Thankyou.