It takes time sometimes, and the reward can be as low as just an N wild card or 1000 pero, or up to pero puddings and wild card 5. You don't always receive it immediately.

As i mentioned before is a bug. Even with help you should be awarded at least with EP (bounty mechanics definitively was changed, don't expect items for aid but there is a chance to get some).

However, before sending a ticket wait 1-2 hours to see a change (see battle list on event icon, all these are logged), i got that issue even being MVP.