As I see it we have two issues here:
1. No films to substantiate the wins (as everyone has already noticed)
2. The winner, not the purported loser, posted the results.
So first we have to hear from Nath who hasn't posted since the fights took place.
My immediate reaction is a rematch, however, if Nath can post films of his first four wins then only the contingent round needs to be refought. Furthermore, any films of Nath's wins in his possission should be allowed to stand (assuming no rules violations), therefore, if he can produce the films of his seven wins then the rematch would only require one win from Nath vs a four win sweep from DejaVu to determine the outcome. Such is the peril of not filming.
Of course either participant has the option of conceeding the duels but even in that case I'd like to see Nath post film of all the duels.
Finally, it can go to a decision.
At this point the ball's in Nath's court.
As to ride alongs I'd frown on it but there's no way that I know of to enforce it. If there is I may consider adding it to the rules for future tournaments.