What do you do if an account was turned over to a collection agency but the original creditor accepted your payment in full?

Contact the original creditor. Provide proof of your payment. They need to retract the account from the collection agency. The account could have been sold to the collection agency or simply assigned to them. For your purposes, it does not matter which situation applies. You paid the original creditor and your credit report needs to reflect this. After they do what they need to do to get the account back; you then dispute the entries with all three credit bureaus. The original account should show as a paid collection and the other collection account should be removed from your credit report entirely.