Being sued by law firm on behalf of HSBC.

Today spoke to the recovery dept and the girl said they had a statement dated August 26. The account was charged off July 31st which confuses me but she said she'd mail it to me. She also stated that "payment" made wasn't by me that she believes it's from the person that purchased the account cause the amounts were equal.

The law office says to contact HSBC for proof of payment. HSBC says contact the collection agency. So Im probably going to send HSBC a debt validation letter.

Today I received a debt validation letter from them stating I requested it and I didn't. (them being the law offices)

How can I dispute that info to the 3 credit bureaus? I assume I have to wait for that August 08 statement I definitely have the February statement in which HSBC says on my credit report that I paid in January yet my statement proves I didn't. I really appreciate you guys replying.