ELAN Financial Services Took payment on a sold account and sent the payment to a collection agency St. Louis Missouri

I was paying off a charged off credit card. Sent a check to ELAN for the full amount in May 2013.  Heard nothing from them until August. They sent me a letter saying they had no rights to the account as of Feb 2013 when they sold the account to Portfolio Recovery.  Few days later I get a letter from Portfolio showing a balance of a penny $0.01 on my account.  ELAN had taken the payment they said they had right to and sent it to the collection agency they sold the account to.  I have filed a Consumer Financial Protection Complaint and a complaint with the Atty General's office in MO.