In my opinion, yes, they could report again, but are very unlikely to do so.
With the collection now being paid, reporting would serve no business purpose on their part.
Additionally, their voluntary deletion indicates that, even prior to payment, they did not want credit reporting hassle issues.
However, considering the unlikely possiblity that they do, you could challenge on the basis that:
(1) they never provided debt verification, and thus reporting is barred based on your unanswered DV.
In my opinion, not a great argument, as your payment would inherently obviate any issue of verification, and their reporting would additionally no longer be an action related to collection on the debt, as their collection was closed upon payment.
(2) payment to the OC terminated their collection authority, and based on the CRA policy that a terminated collection should be deleted by the debt collector, any such reporting should be deleted. No FCRA requriment that they delete the accurate reporting of having had collection authority, but reliance on CRA reporting instructions.
I see little or no reason for the debt collector to want to get involved in those esoteric arguments.
I would assume they will move on to bigger issues.
