Well, it looks like you have been lucky for the last five years. If the collection was legit, and since you paid it off, you admitted its legitimacy, then you are lucky that it is only now appearing. It is already 5 years old, and thus has declined in its adverse affect. The CA reporting the collection and subsequent payment has zero incentive to GW it away. I see no dispute, and suggest that you just have to live with it now.