Status CANCELLED should remove the cooldown on custom rewards
I believe that updating the redemption to have a status of CANCELLED should remove any active cooldowns on the custom reward
I understand that it needs to go into the cooldown state immediately so that other users cannot redeem it again, however setting the status to CANCELLED is our way of signalling that the event did not complete. It's how the streamer says "sorry I can't do that, have your points back".
It makes little sense for the redemption to stay in cooldown when the custom reward has failed to be completed.