Dispute Match Feature
When a player inputs the match results and they are incorrect it would be a nice feature to allow the opponent to dispute this result. An admin would then have to look into the dispute where both players are required to provide photo/video evidence.
The players could upload the evidence to an external site and then submit a link to it so then it doesn't overload your databases.
The next match would be paused while there is a dispute and once it has been resolved the next match can begin.
If an admin doesn't resolve the dispute within a certain time period then the first set of results would be used. The player can then complain to the admin and request a refund.